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SMITHSONIAN

WISCELLANKOLS COLLECTIONS.

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(253.) Lanp axp FresH-WATER SHELLS oF NortH AMERICA. By Grorce W. Tryon, Jr. Part 1V. SrREPOMATIDZ (AMERICAN MELANIANS). 1873. Pp. 490.

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( vii )

SMITHSONIAN MISCELLANEOUS COLLECTIONS. —__—__—_—__— _ 253

LAND AND FRESH-WATER SHELLS

OF

NORTH AMERICA.

Sb ivebi be Ooi ae zB,

(AMERICAN MELANIANS).

BY

GEORGE W. TRYON, Jr.

WASHINGTON: Sern SON LAN LN DELTU TION.

DECEMBER, 1875,

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PREFACE,

Tue following pages contain the results of several years’ study of one of the most interesting and difficult branches of American Conchology. My MS. was completed in 1865, . and I find, upon freshly taking up the subject, that I am inclined to question many of the conclusions at which I had then arrived. A more enlarged acquaintance with fresh-water shells convinces me that a much greater reduction of the number of species than I have attempted must eventually be made; but until the prolific waters of the southern states have been systematically explored and a great collection of specimens obtained, which shall represent every portion of those streams and include as many transitional forms as can be procured, a definitive monograph of our Melanians cannot be written. I am indebted to several kind friends for assist- ance in preparing this work; first of all, to Dr. Isaac Lea, who not only gave me constant access to his noble collection, but on many occasions aided me by comparing specimens and elucidating knotty questions in synonymy. Mr. John G. Anthony, Prof. S. S. Haldeman and the late Dr. Aug. A. Gould, with great liberality, sent to me their types; and in these collections and that of the Academy of Natural Sciences of Philadelphia, I also found types of many of the species described by Say and Conrad. Most of my synonymy is derived from the direct comparison of these typical shells, and to this extent I believe my work will prove to be reliable.

Gu W.., Toe November, 1875.

(v)

. Ly ° Fh leg —s 9 é ye PS

x > =: ty

ADVERTISEMENT.

Tue Smithsonian Institution, realizing the lack of knowledge in refereyte to the land and fresh-water shells of North America/ issued a circular, several years ago, to its correspondents and the friends of science generally, asking contributions of specimens from as many localities as possible, with a view of publishing a report on the subject. In the course of a few years a gratifying re- sponse was made to this appeal from all parts of the con- tinent, in the form of extensive collections of specimens, embracing not only the several species, but those illus- trating geographical distribution.

The specimens thus obtained were placed by the Insti- tution in the hands of specialists, for the preparation of a series of monographs to bear the general title of Land and Fresh-water Shells of North America.” This was subdivided into: I, Pulmonata Geophila, terrestrial uni- valve shells, breathing free air; II, Pulmonata Lim- nophila and Thalassophila, free air breathing univalves, but usually living in or near fresh waters (Limnophila) or the sea ( Thalassophita) ; II, all the operculated land and fresh-water mollusks (excepting the Strepomatide or American Melanians) and embracing the Ampullar- tide, Valvatide, Viviparide, Rissoide, Cyclophoride, Truncatellide, Neritide and Helicinide; IV, the Strep- omatide ; V, the Corbiculade; and VI, the Unionide.

Of these monographs, Parts II and III, by Mr. W. G. Binney, were published in September, 1865. Part I, by Mr. Binney and Mr. T. Bland, in February, 1869 ; and Part V, by Mr. Temple Prime, December, 1865. An elaborate monograph of the /Zjdrobiine, a subfamily of Lissoide, treated in less detail by Mr. Binney in Part

(iii)

lv

Ill, from the pen of Dr. Wm. Stimpson, was published in August, 1865.

Of the two remaining monographs, Part IV is given in the following pages, as prepared by Mr. G. W. Tryon, Jr., and will, it is hoped, tend to facilitate the study of a very intricate group, little understood. No special arrange- ment has been made by the Institution in reference to a monograph of the Unionide (which would form a Part VI) since the many illustrated papers and synopses of the group, published by Mr. Isaac Lea in the Memoirs of the Academy of Natural Sciences, and of the American Philosophical Society, as well as printed privately, ren- der this less necessary. The present work by Mr. Tryon, therefore, completes the series of works on “Land and Fresh-water Shells of North America,” as originally contemplated by the Institution.

JOSEPH HENRY, Secretary Smithsonian Institution.

SMITHSONIAN INSTITUTION, Washington, December, 1873.

LAND AND FRESH-WATER SHELLS

OF

NOrn TE AM TR PGA.

LY.

PRELIMINARY OBSERVATIONS ON THE Family STREPOMATID“4.*

1. Classification.—Swainson, who may be consid- ered the originator of the modern system of classifi- cation of the families and genera of Mollusca (as he was the first general conchologist who, breaking through the trammels of Lamarckian nomenclature, inaugurated the work since so boldly and successfully continued by Dr. Gray and Messrs. H & A. Adams), had, unfortunately, very little knowledge of the affin- ities with the other Mollusca, of the so-called Mela- nians inhabiting both America and the Old World, since he has confounded them with marine shells under his family Turbide; but, notwithstanding this error in the disposition of the whole group, he had the sagacity to separate into numerous, and generally well-characterized, genera, the incongru- ous material which Lamarck had allowed to remain under one generic name,—Melania.

Messrs. H. & A. Adamst approach more closely to the present ideas of conchologists relating to this subject, by separating from, but placing in close neighborhood to, the Cerithiada, their family Mela- niide, of which they admit two Subeunilies, Melani-

*Reprinted from the American Journal of Conchology, Vol. i, No.

2, 1865. + Genera of Recent Mollusca, i, 293.

Vial

ine including those shells with “aperture simple in front, without a distinct notch,” = various genera of Melanians; and a second subfamily, characterized by a notched aperture to the shell, including Mela- nopsis, Lam. Dr. Gray, the only other recent Sys- tematist who has investigated the subject,* adopts a family JJelaniade, including the subfamilies Lisso- ainda, Melaniaina, Triphorina, Scalarina, and Liti- opina, with a heterogeneous assemblage of marine and fluviatile genera; the MMZelaniaina comprising all the genera of American and exotic Melanians, the Cerithians, and the shells which I recently sepa- rated under the family name of Ammnicolida.

It is strange that neither European nor American conchologists who have studied this family have availed themselves until quite recently of the obvi- -ous differences, both in shell and animal, between the American and Oriental forms, for their complete separation, notwithstanding the fact that Prof. Hal- deman showed our Melanians to have a plain or entire mantle-margin, whilst the Oriental species have the mantle-margin fringed, thus allying the latter more closely with the Cerithians than with the so-called American Melanians.t

Dr. Brot, a gentleman who has devoted much attention to the Melanians, remarks$ that the gen- erally adopted classification of the family is very confused and uncertain, but does not attempt to propose a new one.

Mr. Lovell Reeve, who has published an elaborate monograph of the family Sin his preface assigns to the animals of all the ; species a fringed mantle-margin.

Prof. S. S. Haldeman was the first naturalist who detected the difference between our own and the

*List of the Genera of Recent Mollusca. Proceed. Zool. Soc., London, 1847.

7TL he American species are oviparous, the oriental species ovovivip- arous; a more important distinction first pointed out by Dr. Wm. Stimpson in Am. Jour. Sci., xxxviii, July, 1864.

{ Cat. Syst. des Espéces qui composent la Famille des Melaniens.

§ Conchologica Iconica,—Melania, Anculotus, Io, Melatoma.

Vil

Oriental Melanians;* but he did not at that time apply the results of his examinations to their obvi- ous separation into two families.

Mr. Isaac Lea in 1862 proposed a new genus of Melanians, Goniobasis,t which, with other genera previously admitted, and including Melania, Lam., he still continued to regard as belonging to the fam- ily Melaniide, although i in a foot-note he writes, “I very much doubt if we have a single species in the United States which properly belongs to this genus.’

Mr. Theodore Gill, in a recent paper on the classi- fication of our fluviatile Mollusca, assigns the fol- lowing characters to the family Aelaniide :-—

“Teeth of lingual membrane, 3°1:3; gills con- cealed; rostrum moderately produced and entire or simply notched ; foot not produced beyond the head ; branchiz uniserial ; lateral jaws present.

“Aperture of shell acuminate behind; generally channelled at front; size moderate.

“The family of "Melaniide is here restricted to exclude Faunus, Montford (= Pyrena, Lam.,) MWe- lanatria, Bowditch, Melatoma, Sw. (= Clionella ? Gray), Melanopsis, Lam., Vibex, Oken, and Hemi- simus, Sw. These appear to belong to a distinct family, equally distinguished by the projecting foot of the animal and the notch of the aperture of its ‘shell.

“The family may be named JWelanopide.

“The other genera or subgenera that have been proposed scarcely appear to exist innature. * *

“The American A/elaniide form a peculiar sub- family—Ceriphasine.”

Subsequently, in a foot-note,§ Mr. Gill mentions the reason which caused him to make the above

* Amer. Jour. Science, xli, 1, 21. Icon. Encyc. (Am. Ed.), ii, Mol- lusca, p. 84.

+ Proceed. Acad. Nat. Sciences, May, 1862.

t Systematic Arra angement of the Mollusks of the Family Vivipa- ride, and others, inhabiting the United States.—Proc. Acad. Nat. Sci., p. 33, Feb., 1863. § ibid, p. 3d.

Vu

subfamily. “The American Melaniide, so far as I know, have not a fringed mantle, and, consequently, belong to a different group.” We readily admit the propriety of separating the Melanopide from JMe- laniide, as a distinct family, and only wonder that Mr. Gill did not make a family of Ceriphasine, as the distinctive characters of the animal, so far as known to us, and of the shell undoubtedly, are quite as important as those which he assigns to his M/ela- nopide. When we come to consider the geograph- ical distribution of the two groups, the reasons for this separation are still more obvious. We find the Melanopide distributed over both hemispheres, while the Ceriphasine are entirely restricted to North America, to the exclusion almost entirely of the Melanopide, and totally of the fringe-mantled Melanide. We find them inhabiting this faunal province in immense numbers of species, exuberantly varied in form, size, weight and color, presenting a number of genera—in fact, exhibiting all that redun- dancy of character and isolation of position which are the sure indications of a primordial separate existence.”

*It has become fashionable lately to disparage the value of tlie mere Shells as a means of distinguishing generic and family groups, and to rely wholly on such differences as may be found in the animals. Without denying the great importance which should properly be accorded to the latter, we would insist that, in general, the expression of these differences may be observed in the shell, and that at least very few generic distinctions have been made from the study of the animals which have not been also indicated plainly enough by the shells. The study of Malacology is yet in its infancy, and those who figure in it are very apt to give undue importance to the characters on which they rely for building up their systems. ‘To investigate how many characters of form or function have successively been called forth as the most important to stand godfathers at the baptisms of new genera, would be curious, but lamentable.

One thing is certain, that genera founded on the shells alone are always found to be corroborated by the study of the animals, while many genera founded on differences in the animal have remained unverified, and will continue so, owing to the undue importance given to the difference of form relied on for the generic distinction.

We do not regard the differences, so far as discovered, in the animals of our so-called Melanians from the Oriental Melaniide, as alone of sufficient importance to justify their separation; we are con- tented to separate them upon considerations connected with the shell

ix

The publication of Mr. Gill’s paper redirected Prof. Haldeman’s attention to the subject, which he had left unfinished in his investigations at an earlier period; and the result is the publication of a short but important paper in the Proceedings of the Acad- emy of Natural Sciences, September, 1863, entitled, “On Strepomatidee as a Name for a Family of Fluvi- atile Mollusca usually confounded with Melania,” wherein he finally separates our species as a dis- tinct family, remarking that the Oriental Melanians are not so nearly allied to ours as they are to the Cerithiade with which conclusion we cordially agree,

We have, therefore, adopted the name Strepoma- tide as indicating a distinct family, in preference to the prior name of Ceriphasine, the adoption of which would still leave our species in connection, as a sub- family, with shells to which they are not at all closely related.

In endeavoring to eliminate, from the rather con- fused synonymy, generic and subgeneric groups of Strepomatide, some difficulty is encountered at the threshold, on account of the various opinions held by the different naturalists who have studied them, regarding the relative importance which should be assigned to various characters of the shell, in consti- tuting these divisions.

The genus Hemisinus, Swainson (Basistoma, Lea), belongs to Mr. Gill’s family Melanopide. The little Paludomus brevis, D’Orb., of the West Indies, is apparently the American representative of an exotic genus; the large tuberculate Melanians of Central America, and the smooth Pachycheili of that country and of Mexico, probably do not belong to our family Strepomatide.

Thus the range of the species of the family may

also, and with geographical distribution, believing, however, that other and more important distinctive characters will reward the industry and skill of some future malacologist.

x

be considered as restricted within the borders of the

United States.* Swainson formed the following curious generic system for the shells under consideration :}

Family TURBIDZ.

(Subfamilies Ampullarine, Melaniane, Turbine, Janthine.)

Subfamily MELANIANZ.

Genus PaLtupomus, Swainson.

Subgenus Ancutosa, Say.

Genus Meant, Lam.

Subgenus Hemisrnus, Swainson.

Genus Meranopsis, Lam. Subgenus Me1arusus, Swainson.

Subfusiform, the base contracted, and the aperture and spire nearly equal. 1species. America. (= Io.)

Fig. 1.

Subgenus Mertatoma, Swainson.

Fusiform, longitudinally ribbed ; a deep sinus at the top of the outer lip; base contracted, channel wide. M. costata. (This species, mistaken by some for our genus Schizostoma, is actually an exotic marine shell = genus Clionella. A copy of Swainson’s figure is subjoined (fig. 1).

Genus CERITHIDEA, Swainson. Clayate, cerithiform ; aperture subemarginate. oS

Subgenus CeriTHIpEA, Swainson.

Shell light, decollated ; outer lip semicircular, dilated by a flattened border; aperture emarginate. C. lineolata, Griff. Cuov.,t.. 14,.f.4.. C. fragilis/1bid., t. 32; 1.24) |G Pome MIDES. )

* Three or four are extra-limital, inhabiting Cuba and Mexico; but

these do not constitute one per cent. of the whole number of species. + Manual of Malacology, 1840.

Xl

~

Subgenus CerrpHasia, Swainson.

Cerithiform ; outer lip thin, dilated at the base ; aperture small, slightly emarginate, without any internal groove; inner lip thin. C.sulcata, Sw., fig. 38 (figs. ,

2 and 3 of this work). Founded Mig 24: en Bs on certain Ohio shells resembling Cerithidea?

It will be noticed that in the above classification JZela- Jusus is a subgenus of Jelan- opsis, which belongs to the family Melanopide, while Ce- riphasia is a subgenus of Cerithidea, which includes shells belonging to the family Cerithiide!

Dr. Gray (Proceed. Zool. Soc., London, 1847, p. 153) makes the following division of his subfamily Melaniaina, which in many respects is very correct. He separates the exotic genera from the American, and of the latter quotes the following :

AncuLotvs, Say, 1825.

Anculosa, Swains., 1840 A. premorsa, Say. Melanopsis, sp., Moricand M. crenocarina.* Anculosa, sp., Anthony Ane. rubiginosa. Melania, sp., Say Melan. obovata.

Meratoma, Anthony, 184—? not Swains., 1840. Melat. altilis, Anthony. Io, Lea, 1832. Fusus, sp., Say, 1825.

Melafusus, Swains., 1840. Melania, sp., Say—WMel. armigera, Say.

; Fusus fluviatilis, Say.

CERIPHASIA, Swains., 1840. Gray, Syn., 1844.

Melania, sp., Say—Ceriphasia sulcata, Swains. ? Telescopella. Melania, sp., Say—Mel. undulata, Say.

GLOTELLA, Gray. Melania armigera, Say.

*— Verena, H. & A. Adams; certainly not an Anculosa.—T.

X11

Messrs. H. & A. Adams (Genera of Recent Mol- lusca) propose the following classification : *—

‘‘ CeRIPHASIA, Swainson (i, p. 297.)

Shell subfusiform, whorls transversely sulcate, the last angu- lated; spire acuminated; aperture small, produced in front, with a small groove-like canal at the fore part; outer lip thin, posteriorly sinuated.

Syn. Telescopella, Gray.

Ex. C. canaliculata, Say, t. 31, f. 6.

The shell of Ceriphasia is covered with a dark-green epider- mis, and is more like that of Jo than any other of this family ; it may, however, be distinguished from Jo by the beak being shorter, and by the whorls being sulcated and not spiny.”

acuta, Lea. luteosa, Gould. Alexandrensis, Lea. Ordiana, Lea. annulifera, Conr. regularis, Lea. canaliculata, Say. spurca, Lea. elongata, Lea. subularis, Lea. exarata, Lea. sulcosa, Lea. Haleiana, Lea. symmetrica, Hald. Kirtlandiana, Lea. Vainafa, Gould. lugubris, Lea. Virginica, Gmel.t

‘‘ Genus PacuycHEILvs, Lea (i, 298.)

Opereulum suborbicular, of several whorls. Shell subfusi- formly conical, smooth, solid ; aperture ovate, entire anteriorly ; columellar lip thickened posteriorly ; outer lip thick.

The chief peculiarity of this genus is the thickened outer lip ; it differs from Melanopsis in having no sinus at the fore part of the aperture, and from Melania in having a callous columella.

* We quote the full lists of species given by Messrs. Adams, in order that the insufficiency of their genera may become more apparent from the incongruous assemblage of shells of which they have composed them. Prof. Haldeman writes (Proceed. Acad. Nat. Sciences, p. 274, Sept. 1863): ‘‘The groups of Messrs. H. & A. Adams often indicate merely sections; and sectional names given as generic are scientifi- cally erroneous, because they erect certain species into genera and subgenera only when they belong to extensive groups, requiring numerous specific names, whilst the same amount of character goes for nothing in groups which have but few species.”

+ The species here assembled are principally Gonitobases, but are included in Ceriphasia evidently because they are ‘‘ transversely sul- cate.” DM. Virginica and its synonyme muiltilineata are again introduced in Juga, a subgenus of Vibex, Oken!

M. canaliculata, Say, is introduced, but undulata, Say, does not appear, while jilum, Lea, a very closely allied species, is placed in Elimia, a subgenus of Jo.

X11

The operculum has the nucleus subcentral, and is composed of two or three spiral revolutions. dubiosus, Say. ferrugineus, Lea. simplex, Say.* ** Subgenus Porapoma, Swainson (i, 299.) Shell ovate, solid; spire short, whorls smooth; inner lip

somewhat thickened; aperture produced in front; outer lip acute, simple.

depygis, Say. ovoideus, Lea. gracilis, Lea. rufescens, Lea. inornatus, Anth. sordidus, Lea. levigatus, Lea. subcylindraceus, Lea. Niagarensis, Lea. subsolidus, Lea. Ocoeensis, Lea. Warderianus, Lea.

** Genus Io, Lea (i, p. 299.)

Shell subfusiform, whorls spinose; aperture large, ovate, dilated anteriorly, produced in front into a grooved beak ; outer lip simple, acute.

Syn. Melafusus, Swains., Glotella, Gray.

Ex. I. fluviatilis, Say, t. 31, f. 8. Operculum, f. 8, a, b.

The species of Jo inhabit the rivers of North America; the shells, like those of most of the Melaniide, are covered with a brown, black or olivaceous epidermis, and are remarkable for the peculiar elongation of the axis anteriorly, and for the spi- nose nature of the last whorl.

armigera, Lea. pernodosa, Lea. Duttoniana, Lea. plicata, Lea. Florentiana, Lea. robulina, Anthony. Jluviatilis, Say. spinigera, Lea. Susiformis, Say. spinosa, Lea. nobilis, Lea. tenebrosa, Lea. pagodula, Gld. tuberculata, Lea. f

‘‘ Subgen. Ermira, H. & A. Adams (i, p. 300.)

Shell fusiformly ovate; whorls reticulate or nodulose, cari- nate in the middle; aperture greatly produced anteriorly ; outer lip thin, simple, acute.

*The genus Pachycheilus was instituted by Mr. Lea to comprise a certain form of shells attaining their greatest numerical development in Central America. There are no shells inhabiting the United States which are congeneric with these; and Messrs. Adams have entirely mistaken the scope of the genus in including such species as simplex.

simplex, Say, which Messrs. Adams place in the genus Pachy- cheilus as typical!

tAmong the species here enumerated are Angitreme, Anculose, Lithasiev, Strephobases, Goniobases, and Pleurocere. J. pagodula is an exotic species, and does not belong to the genus.

X1V

acuticarinata, Lea. catenoides, Lea. apis, Lea. elevata, Lea. bella, Conrad. jilum, Lea. Boykiniana, Lea. Holstonia, Lea. caliginosa, Lea. nodulosa, Lea. cancellata, Say. Potosiensis, Lea. carinocostata, Lea. spinalis, Lea. catenaria, Say. torta, Lea.

‘¢ MeLanta, Lamarck.

Subgen. Merasma, H. & A. Apams (i, p. 300.*) Shell solid; spire elevated, whorls smooth, longitudinally plicate ; aperture produced anteriorly ; inner lip simple, thin ; outer lip acute, simple.

blanda, Lea. Deshayesiana, Lea. brevispira, Anthony. Edgariana, Lea. claveformis, Lea. laqueata, Say. Comma, Conr. Lecontiana, Lea. concinna, Lea. nitens, Lea. costulata, Lea. plicatula, Lea. crebricostata, Lea. plicifera, Lea.

Curreyana, Lea.

‘‘Genus Hemisinus, Swainson (i, 302.

Shell subulate; whorls smooth, simple, numerous; aperture ovate, anteriorly contracted, canaliculate and emarginate in front; outer lip thin, crenulated at the edge.

Syn. Tania, Gray, Basistoma, Lea.

Ex. H. lineolatus, Wood, t. 32, f. 2, a, D.

This genus comprises many fine species of fresh-water shells, principally from South America, though a few have been re- garded as inhabitants of other countries.

bulbasus, Gould. symmetricus, Conr. lineolatus, Wood.t

‘*Genus Visex, Oken (i, 303.)

Shell turreted ; whorls tuberculated, spirally ridged or muri- cate; aperture subcircular, produced, and broadly channelled in front; outer lip thin, simple.

Syn. Claviger, Hald., Melania, Swains., not Lamarck.

‘““ Subgenus Juaa, H. & A. Adams (i, 304.)

Shell thin; whorls rounded, transversely lirate or furnished with elevated transverse lines; aperture produced anteriorly ; outer lip simple, acute.

*This genus the plicate species of Goniobasis. M. brevispira, however, is never plicate, although included with the species.

+ The first two enumerated do not belong to this genus, nor have they the slightest aflinity with any of its species.—G. W. T., JR.

XV

Buddii, Say.* proxwima, Say. circincta, Lea. Schiedeana, Phil. exilis, Hald. silicula, Gld. multilineata, Say. striata, Lea. obruta, Lea. Troostiana, Lea. occata, Hinds. Virginica, Say.

proteus, Lea.

** Genus Grrotoma, Shuttleworth (i, 305.)

Shell ovate, turreted ; whorls transversely sulcate ; aperture oblong; inner lip thickened, with a posterior callosity ; outer lip thin, with a deep, narrow, posterior fissure.

Syn. Schizostoma, Lea, not Bronn, Melatoma, Anthony, not Swainson, Schizocheilus, Lea.

Ex. G. ovoidea, Shuttleworth, t. 32, f. 4, a, bd.

The fissure in the outer lip is wanting or obsolete in the sub- genus Megara, the species of which in other respects closely resemble those of Gyrotoma proper. Both groups are American in their geographical distribution.

altilis, Anthony. excisa, Lea. Babylonica, Lea. Foremani, Lea. Buddii, Lea. Suniculata, Lea. conica, Say. incisa, Lea. constricta, Lea. laciniata, Lea. curta, Migh.? ovoidea, Shuttl. curvata, Say. pagoda, Lea. cylindracea, Migh.? pyramidata, Shuttl.+

** Subgenus Mrecara, H. & A. Adams (i, p. 306.)

Shell ovate, solid; whorls transversely sulcate; aperture ovate-oblong, subcanaliculated anteriorly ; outer lip thin, sim- ple, acute.

alveare, Conr. fToeydei, Lea. arctata, Lea. impressa, Lea. auriculeformis, Lea. lateralis, Lea. basalis, Lea. lima, Conr. brevis, Lea. oliva, Lea. crebristriata, Lea. olivula, Conr. harpa, Lea. ovalis, Lea. Haysiana, Lea. pumila, Lea.

*Should read Buddii, Lea. MM. exilis, Hald., and proxima, Say, certainly do not belong here. I have already remarked upon MW. Vir- ginica and multilineata.

+Mr. Anthony never described Gyrotoma altilis, ranked among these species. (G. conica, Say, is the young of Plewrocera canaliculata. There are, besides, frequent mistakes in all these lists, in misquoting authorities, T.

XV1

solida, Lea. . undulata, Say. torquata, Lea. Vanuxemiana, Lea.*

‘* Genus Leproxis, Rafinesque (i, 507.)

Shell ovate or globose, solid, subperforate ; spire very short ? aperture oval; inner lip with a posterior callosity, often ante- riorly callous and produced; outer lip thin, sinuous with a posterior, ascending canal.

Syn. Anculotus, Say, Anculosa, Swains., Ancylotus, Herm.

Ex. L. prerosa, Say, t. 32, fig. 6, a, b.

The species of this genus are peculiar to the North American rivers; the spire of the shell has a truncated, eroded apex, and, in the typical species, the shell is solid and subglobose, with the aperture simple in front,

abrupta, Lea. pilula, Lea. angulata, Conr. pisum, Hald. crassa, Hald. plicata, Conr. Jlammata, Lea. prerosa, Say. Suliginosa, Lea. pumilis, Conv. Jusca, Hald. rubiginosa, Lea. Susiformis, Lea. squalida, Lea. gibbosa, Lea. subglobosa, Say. globula, Lea. teeniata, Say. Griffithsiana, Lea. tintinnabulum, Lea. Hildrethiana, Lea. trivittatus, DeKay. integra, Say. Troostiana, Lea. melanoides, Conr. turgida, Hald. Nickliniana, Lea. variabilis, Lea. nigrescens, Cony. virgata, Lea. obtusa, Lea. viridis, Lea.t

picta, Conr.

‘** Subgenus Nitocris, H. & A. Adams (i, 308.)

Shell thin, subglobose; whorls angulated, often carinate ; inner lip subtruncate, or ending in a tubercle.

carinata, Lea. dilatata, Conr. costata, Lea. dissimilis, Say. dentata, Couth. ebena, Lea.

*Here we find shells belonging to several groups, as pumila, Lea, alveare, Conr., and torquata, Lea, to Strephobasis; lima, Conr., and solida, Lea, to Lithasia; undulata, Say, to Plewrocera. Hoeydei, Lea, was never described. Can it be intended for Hydei, Conr.? The spe- cies are generally, however, the ponderous Goniobases of Northern Alabama.

+In the species of this genus there are several errors, some quite elongated forms being included; also, a species of Lithasia.

Xvi

inflata Lea. occidentalis, Lea.* Kirtlandiana, Anth. Rogersii, Conr. monodontoides, Gld. subcarinata, Hald.

** Subgenus Lirmasta, Lea (i, 308).

Shell thick, solid, ovate; whorls gibbose or tuberculated at the hind part ; aperture subcanaliculated and produced in front ; inner lip with a callus posteriorly, subtruncate anteriorly.

genicula, Hald. salebrosa, Conr. neritiformis, Desh.f semigranulosa, Desh.” obovata, Say.

Chenu (Manuel de Conchyliologie) principally fol- lows the arrangement of Messrs. Adams.

Lovell Reeve monographs separately Jo, Hemis- inus, Anculotus and Melatoma, and treats all the species not included in those genera as Melanie. He says, “Advantage might have been taken of the labors of systematists to- have distributed them into further genera; but more materials are needed for their elucidation than we at present possess,t

R. J. Shuttleworth (Mittheil. der Nat.-forsch. Ge- sellsch. in Bern., No. 50, p. 88) proposed, July 22, 1845, a new American genus of fluviatile shells, which he characterized as follows :—

*— jin some respects Mudalia, Hald., and Somatogyrus, Gill.

+ Neritiformis, Desh., is an Anculosa, and is a syn. of A. prerosa, Say.

tIt is very much to be regretted that Mr. Reeve did not make some kind of a division, however arbitrary, of the immense material entering into his magnificent monograph of Melania, as he has pub- lished it. Species from all countries, without regard to external resemblances, are, in many cases, grouped on its plates indiscrim- inately, rendering the identification of shells by its aid exceedingly difficult. Even several of the species are duplicated in description and illustration in the monographs of Melania, Jo and Anculotus.

While on the subject of Mr. Reeve’s monograph we cannot refrain from condemning the substitution of new descriptions of the species for those originally given. The descriptions of Mr. Reeve in numer- ous cases entirely neglect the most important specific characters. The plates frequently do not represent the species for which they are intended; but in this Mr. Reeve has been undoubtedly deceived by wrongly-named specimens.

It is a strange fact that, notwithstanding the length of time which bas elapsed since very many of our Melanians and Unios have been described, and the large number which have been sent to Europe in scientific exchanges, European conchologists are still to a great extent ignorant of the most prominent and important specific characters,

L.F. W.S.IV.

XVill

Gyrotoma.— Shell turreted; columella incurved, above callously thickened ; aperture oval, subeffuse at the base; lip simple, acute, narrowly profoundly fissured above.

** Animal.—Operculum corneous, spiral.”

This forms one of the most distinct of the genera of Strepomatide. Mr. Lea, however, anticipated Mr. Shuttleworth’s discovery.

Dr. Brot, in his admirable Systematic Catalogue of the Melanians,” proposes, instead of the genera 1 of H. & A. Adams, a series of sections, which are gen- erally excellent, for the arrangement of the species. The following is his plan :—

1. Operculum concentric. Genus Patupomus, Swainson.

2. Operculum spiral or subspiral. * Aperture entire. Genus Leptoxis, Raf. (Anculotus, Say ; Anculosa, Conr.) Genus Mevanta, Lam. Group a, type canaliculata, Say. b, ‘* curvilabris, Anth. eer gh teh Honsvana. sued.

(7. ah Be Virginica, Say.

: costulata, Lea.

dy, (ce, perangulata, Conr. d, ‘* simplex, Say. e, ‘* Warderiana, Lea. Sr nes “* mupera, Say. bei ae (European. )

Ona glaphyra, Morelet. c, ‘¢ nigritina, Morelet. (All the other groups of this section, thirteen in number, are exotic.) ** Aperture produced in front. Genus Io, Lea. *** Anerture truncate in front. (Mevanopsis, HemisInvs.) **** Anerture posteriorly sinuate. Genus Gyrotoma, Shuttlw. ***** Anerture sinuate in front and posteriorly. (Pirena, Lam.)

a, ‘* levissima, Sowb. J)

Xs

Passing to American authors, we find Mr. Say was the first to eliminate a native genus from the genus Melania. Inhis description of Melania prerosa, he says, This shell does not seem to correspond with the genus to which I have for the present referred it; and, owing to the configuration of the base of the columella, if it is not a Melanopsis, it is probable its station will be between the genera JMelania and Agathina. I propose for it the generic name of