Sine TS : SGI Ci Seren 08 eg BEEN ee ee ce Ne RISEN GN I peat TT ree ta! Pea eek MEN ieee) 5 teers ota SRM BRE Oe ee ee peseene oe aera x = eee Senn, © PRIN PV EN EO IVETE ET EWES iA. See eee ee PUNTA EAT AE iden ee) Va iGQvya ait _— w = -_= . io ae “ e us a a. te vp oc a = i Yip > : 5 : : i: = S = = as S) = re) = 3 ws z -! 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TTY OO ps (e) Se z MS \S 2 e z a ag). . > hs — ~~” ene ae 3 : 5 OILNLILSNI_ NVINOSHLINS S31YVYYSIT LIBRARIES SMITHSONIAN INSTITUTION | , S 5 ra gins A hs nn aa". — rt Ce uw z ts _ ow. = ea | we = “Uj 5 es S ce = LSNI_NVINOSHLIWS ~Saluvuag 7 Ut BRARI ES_ SMITHSONIAN, INSTITUTION _ NOLL = = : fo) —s ra) ES _— oO wo ‘ —_ o —, o I a SY 5 = 5 oe > fod SAWS sins =) — = a Wg 2 Z ? 2 IES SMITHSONIAN INSTITUTION NOILNLILSNI NVINOSHLINS S3INYVYUSIT_ LIBRAI wn " =< 2 Ww” z= ” . = ‘. = mm = = LY, < = a : ¥ tp, Zz s 2 Sa i l= Z, - Ss = = =r = > = 33 LSNI NVINOSHLINS S3ZIYVYYSIT LIBRARIES SMITHSONIAN INSTITUTION NOILN 2 2 2 wn = i 5 Leal = load = oe e pe c < SA < = ““ oa ~{ a el fhe ro] > HY = ro) aly 5 & za = za ae) z= a TES SMITHSONIAN INSTITUTION NOILNLILSNI NVINOSHLIWS Saluvudiy LIBRA ro) = S = ae S pa = * = o < = o p= Ne a > 2) re = aw = > reg > ; = > a r 2 = xz i a 2 A g m ASNI_NVINOSHLINS, SA1UVYAIT_ LIBRARIES, SMITHSONIAN INSTITUTION NOILN v =~ 4 fos: ; % SS > = z= Ee R as o y os pig 2M” & a \ ee o Wig = g EW a ” 5 21ES SMITHSONIAN INSTITUTION NOILNLILSNI NVINOSHLINS S31YVYSIT_ us 2 wy 2 - Zz eae n =e a) ” o . = a = = a < § a < a < c er a = = = a5) oy = = | LSNI” NVINOSHLINS S3INVYUGIT LIBRARIES SMITHSONIAN_INSTITUTION NOILNL Bi ve = E z s E z = i= a = = = > = > =) > = Ps) = = = - = = FY = ms o SZ z wo = RIES) SMITHSONIAN INSTITUTION NOILNLILSNI NVINOSHLINS S31uVY giq ui BRA a= as = op, = 7 = x = = 2 z AWE = SM =e OS > —- = >’ s >" = a 2 = 7 > “S z ” ~ JLSNI_NVINOSHLINS Sa1YVYGIT_LIBRARIES SMITHSONIAN INSTITUTION NOILNL Rs z Sey eel Palit a ee cih pe, 2 | = Laetn 7 ae < re ; on jigs . | a Pata. i Fee A: Pi ge: ee A DESCRIPTIVE CATALOGUE OF THE NAIADES, OR PEARLY FRESH- WATER MUSSELS Division of Mother 1 esonad LALIOrY | BY CHARLES TORREY SIMPSON C Sey ~] PART I UNIONIDA TRUNCILLA — MARGARITANA BRYANT WALKER SMITHSON DETROIT, MICHIGAN 914 : MAY 03 1988 . LIBRARIES alk g fai; aii eae Me es ae a Na: tik | ays aris a Pra ite eee ny a | a é : ARI Te ry eS vie % ie & yoga of 2 if Ss) qo jd0 cae "at Ne We pee a ane E: 4 i eine | o i) ie ORAL ib ee = < arate ca ee ace iy: $< Fl Fi : : _ é m. i be = ms ‘ - 4) Lae 4) a, . f a) y *, ~ | oar ee nT bass TOON Vy aes re © rue) | . \} INTRODUCTION. This work was begun immediately after the publication of my “Synopsis of the Naiades” in 1900 and was completed, substantially as it now appears, in the latter part of 1901. It was prepared in anticipation of an immediate publication with illustrations of all the species. But owing to the failure of that expectation and my removal to Florida in 1902, the MSS. was laid aside and nothing further done upon it until recently. There can be no doubt but that the lack of a convenient handbook of the Unionide, which would enable the student to have adequate descriptions of all the species before him, has had much to do with the comparative neglect that the family has suffered, especially in this country, where it is so remark- ably and characteristically developed. The literature is scat- tered, expensive, largely out of print and in many cases prac- tically unattainable. The necessary consequence has been that the identification of nearly all of the rarer species has been based upon the individual conceptions of the more prominent collectors rather than on a careful study of the original de- scriptions. The resulting uncertainty and misapprehension as to the correct understanding of many of the species is widely prevalent among collectors and, even in the museums, there is not a little incorrectly named material. It is with the hope of supplying, to some extent at least, this deficiency that it has been deemed advisable to publish this work in its present form, without illustrations. What we should have in this country is a fully illustrated manual of the Naiades such as has been published on the land and fresh-water univalves. But, unfortunately, there seems to be no prospect of a publication of this kind and, in its absence, it has been thought that the gathering together of descriptions of all the species in a single volume would be of service to those already interested in our native species and might tend to excite a greater interest among those, who might-be inclined to collect and study them, but who have been deterred by the lack of accessible literature. If this result shall be attained, 1V INTRODUCTION the purpose of this publication will have been fully accom- plished. While there is no doubt but that the increase of our genera! knowledge of the anatomy and embryology of the family will lead to and necessitate many changes in the arrangement pro- posed in the Synopsis, a large part of the more recent work that has been done is still in a tentative and formative con- dition and will be subject to more or less modification in the future, and many important groups still await the compre- hensive examination that will be required to definitely deter- mine their systematic position. As this work is intended to be a companion volume to the Synopsis and is especially intended to facilitate the study of the species, it has been deemed best to retain the systematic portion substantially as given in that work. In order to bring the subject down to date, I have inserted in their proper places the original descriptions of all the North American species that have been published since the Synopsis appeared and also those of such foreign species as have been brought to my attention. But my long continued residence in the south, away from the large museums and without library facilities, has prevented me from expressing any personal opin- ion as to their validity and they are published without critical examination and simply for what they may be worth. As far as possible I have inserted them in what appears to be their proper systematic position, but in far too many cases, the re- prehensible habit of many authors of describing supposed new species without any comparative remarks as to their relation to those already described and of ignoring all the recent ad- vances in classification has compelled their reference to the class—“incerte sedis.” I have not attempted to include the perennial vagaries of the Continental conchologists in dealing with the European fauna. I have already had occasion to express my opinion of their work in the Synopsis and have seen no reason to change it. Since the publication of the Synopsis, it appears to have been demonstrated that in the genus Parreysia the embryos INTRODUCTION Vv are contained in all four of the branchie, and this would place this genus in the group I have called “Tetragenee.” The char- acters of the shells of Parreysia would indicate that they should be placed in Rosanoramphus as they have mostly zig- zag radial beak sculpture. It is quite probable that this and some other genera may be connecting links between the two great groups. Gravid material of two South African species has been examined by the author since writing the Synopsis. These and allied species had been placed provisionally in Nodularia, but they seem to be true Unios. None of the South African shells of this group that I had examined were in condition to show the beak sculpture. The attempt to systematically classify much of the Asiatic and South African material and some of that of South America was largely tentative and it is quite likely that many changes will have to be made when more and better conchological and anatomical material can be carefully studied. When we are able to examine gravid material of all the larger groups, then and not till then will it be possible to be certain of the relation- ship of a large number of forms. The only guide to classification in a great many cases was the shell, and such material as was accessible was often in bad condition or totally insufficient in quantity and the beaks in nineteen cases out of twenty were so eroded that it was impossible to determine anything accurately from them. In other cases only a figure and a description were accessible and in still others only a description. The character of dimor- phism is a very important one, but to be of much use to the student, he should possess male and female shells of species, which are so developed. For example, in the genus Neplhro- naias many of the male shells cannot be distinguished from the shells of Unios by any means I know of, but the female shells of such species differ from the males in possessing a marsupial swelling, while those of Unio do not have it. The following table taken from the Synopsis will show the classification of the genera and higher groups. mm. ‘ inge with schizodont teeth; embryo a glochid Family Unionide. H (Exobranchie.) gills. embryos in outer or all four of the Beak sculpture more or less concentric; Unionine. Subfamily Ovisacs distinctly marked out by a sulcus. Ovisacs not separated by a sulcus. Te Male and female shells different. Male and female shells alike. Marsupium outer gills and forming smooth pads. SYNOPSIS OF THER GENERA OF (Heterogene.) Female shell inflated at base in front of posterior ridge; marsu- pium in hinder part of outer gills. (Digena.) Female shell inflated behind, above posterior ridge. (Mesogena.) Marsupium a few ovisacs in the center of outer gills. (Ptychogene. ) Marsupium occupying the whole outer gills in a series of folds. (Eschatigena. ) Marsupium occupying the outer border of outer gills. (Diagene.) : Ovisacs filling the outer gills, running crosswise. (Homogena.) filling thé entire (Tetragenee.) Marsupium filling all four gills, forming smooth pads; beak cavi- _ ties deep. NATADES., Truncilla Rafinesque. Micromya Agassiz. Lampsilis Rafinesque. Friersonia Ortmann. Pseudospatha Simpson. Hyriopsis Conrad. Chamberlainia Simpson. Simpsonia Rochebrune. Cristaria Schumacher. Lepidodesma Simpson. Pilsbryoconcha Simpson. Medionidus Simpson. Nephronaias Crosse and Fischer. Glebula Conrad. Obovaria Rafinesque. Plagiola Rafinesque. Tritogonia Agassiz. Hemilastena Agassiz. Cyprogenia Agassiz. Obliquaria Rafinesque. Ptychobranchus Simpson. Dromus Simpson. Strophitus Rafinesque. Anodonta Bruguiere. Colletopterum Bourguignat. Gabillotia Servain. Leguminaia Conrad. Lastena Rafinesque. Solenaia Conrad. Gonidea Conrad. Anodontoides Simpson. Strophitus Rafinesque. Pegias Simpson. Arcidens Simpson. Arkansia Ortmann and Walker. Symphynota Lea. Alasmidonta ‘Say. Margaritana Schumacher. Unio Retzius. Pleurobema Rafinesque. Ouadrula Rafinesque. Schistodesmus Simpson. Gibbosula Simpson. Cuneopsis Simpson. Nodularia Conrad. Harmandia Rochebrune. Grandidieria Bourguignat. Physunio Simpson. Simpsonella Cockerell. Pressidens VWaas. Pseudodon Gould. a’ mre | (Rosanorhamphus.) Parreysia Conrad. Beak sculpture generally zigzag- Ptychorhynchus Simpson. radial; epidermis often bright. Virgus Simpson. Cristadens Simpson. Rectidens ‘Simpson. Lamellidens Simpson. Trapezoideus Simpson. Arconaia Conrad. Pseudavicula Simpson. Arcidopsis Simpson. Hinge with schizodont teeth; embryo a glochidium. Castalina von [thering. Castaliella Simpson. Callonaia Simpson. Hyria Lamarck. Prisodon Schumacher. Diplodon Spix. (Lamphorhamphus.) Beak sculpture radial, often curved shell dull colored. Subfamily Hyriane. Beak sculpture radial, male (Endobranchia. ) and female shells alike; marsupium filling the inner Family Unionide. gills. Tetraplodon Spix. { Spatha Lea. Mutela Scopoli. Chelidonopsis Ancey. Brazszea Bourguignat. Family Mutelide. Arthropteron Rochebrune. Hinge teeth taxodont; male and female shells Pleiodon Conrad. alike; embryo a lasidium. | Monocondylea dOrbigny. Theringella Pilsbry. Fossula Wea. Leila Gray. Anodontitis Brugutere. Muacetopoda d’Orbigny. Vili INTRODUCTION I have endeavored to give fairly full descriptions of all the shell characters where they are of any importance and to de- scribe the different features of the female shells of dimorphic species. Comparisons have been made between closely related species or those which resemble each other. In a few cases changes have been made, as it has been pos- sible to examine gravid material since the writing of the Sy- nopsis, which proved that the position assigned to these forms was erroneous. The subject is brought down to January 1, 1913. But I have included references to the new genera described by Dr. Haas in January, which had been illustrated prior to that time in the new edition of the Conchylien Cabinet. CHARLES Torrey SIMPSON. Little River, Florida. February I, 1913. CONTENTS LTPVESO EIGEN SIU or ar, a a etalncticrorenien alaGes, Ye nae ass a tee ae ew es es < eeriutey UVLO We aa ch oe eee bo a wie v led Savoie Uniomines 2. ob cre mesa txs. + aclse s PE ROGE NAM sakes a's: cbr ori ic Sis alk o «sya d.n's ore x ee Cncsy Ve CIN MPI So) SOAR eer re ot NEUE RON Nee er ane Me es Ges Le IB CONIEP SRD 1S Hea Other eea ae... iS -2 iS, ee WL IESE RSONGEAT ae 8. ee ee PSE CMOS ENTE Ase Mec. ic. oi oid eee eos toa! see 6 FAMIMOPSIS U) - esp cs eek Ce et Bae UE IGENMIDONS weiss cue Gers Sei ete. os s Oa PET EMRONGAEAS | OPIS cit wien s coc o's we + x Uebeysis \ SLTET RGAE A TA Sat >a me OVA N te cere en antee «oc tes, Bete ’ PABAGCTORA oc. l inet eatery eee cS oe ls 1 TOG Net ee Ey ee et UP es dae ee Ly 8 fa RE COG bree es, ges oe ws agi Mace esa Ps CA ds CONTERY CO DLS 0. Val lis Ce ELSTON “PB POR CTS OTANI: DP Diode a ie op ae PARVOHORRANCEIUS) 2.5000 one oe hs a ks on CONTENTS ESOHATIGRN AS. chs sso 2 thre Gian ws asta s ile ee 340 DROM US s.5 o5 co. « one See A ee RE re 341 DIAGEINAS, 2-5 4 Fear} me. eek pie eee te ee eee 344 SUROPE UTE: 1. sys hao Ss er alee cae eee 344 FLOMOGEN AS... . deh ore, wicrier sates wiv cen rede Oh eed 358 ANODOMNTA.—£ fy wavade tine Nee tone tae ee 358 COLLETORI BRIM: jc; tigs ates iad oe. oR 438 COMBI EO ine pred veers ee oa rk ee 440 EROUMINAIAN: oy one ad ee ero wade ds hoe 444 LQASITEIN Bs (ols ees acts JERE Rg? 452 SORBNALAY © 1". Agere Gece ae een em 455 Gon mapa} PO le eee oe eee 463 A TODO BOTIES 10.) ae AC cou eh ee ee 466 DEGIAS 5.3 ks Sapo toa Oe tay ete ee 472 ARGCIDENG Fide tcc.a Pedi hes ae ate ees 475 ARRA NBT ARyo6s iO. athe tae et ek met ten 477 SVYMPH Wie: ued lee ee ee oe 480 ALAS MIDOAMDA) © (0G tka errr pe emenieee eee ees 492 MARGARITANA) 2 hota ok Rate een need ae SII WINIO! Saks ses D8 caters eabek See eee 527 PUEUROBEMA |) 43-. 5. aus ae ee ne eae 732 (PETRAGCENE ES” (2.02/32. 4U ces eR OR a eae ee ae 810 COUAD RIA. janastn sont choc deg eae Ear 811 SCHISTODESMUS: +. .080s. ee eee cone aw eug 939 (GIBBOMITI A 3.34.5, ctl ® foe eaters O4I CUBBOPSIS” |.:69 ae Bane ee Che ae ee 943 Siubiamathy- fy rian’ 2 cy. 5.) savor oer wee ae ee 949 ROSAWORHAMPHUS, jo. 0x. ceS sido 3 een eee 949 Gentis NODUEARIA, +57 8cke yaa thoes 1051 PRYSUNIO (opi x oe cathe ee es 5s 1062 SIMPSONS Ar vac x. Satu cies ee SR, 5 og 1069 PRESSIDENS, ie Gs Sad te oee eee ops 2 cee 1077 PSEUDODON™ s.::5 45412) Ere it n> Seales 1079 CONTENTS CRisiApen ss - 07 es. ReCTIDENS? Sesu 404. PAMELEIDHNS . 2.7... TRAPEZOIDEUS ...... PARICOINPAUIAL Mane Pe hs I,AMPHORHAMPHUS ....... LetRAPLODON |... 2. late te 5 ene oy x Panty, WOU WE Igl DAR. fii 8, Geis; SPATHA ». o. eels oe. NURI Acre tea sein eke te CHELIDONOPSIS ..... RAZA os saa se. ARTHROPTERON ..... PEETODON, © oo dkoanw es MONOCONDYI,ASA THERINGELLA BOsstiall focttns eee Te eaie Ae ao cae ANODONTIIES 22. 3. 34 MycrToropa ........ muddenda-et Cormgenda yack... wate Ot. PcbliGAabiOM:, +)... s%. eo. oes Hiren mete Ne mre, Se ee Ale eet DESCRIPTIVE CATALOGUE OF THE NAIADES Family UNIONIDAE. Shell nacreous, with a thick epidermis ; beaks usually sculp- tured, often showing the remains of the nuclear shell ; ligament opisthodetic ; hinge with or without teeth, though with vestiges of them in every genus; when present schizodont and arranged as pseudocardinals and laterals; pallial line usually simple; prismatic border ordinarily narrow. Animal with labial palpi almost always wider than long’; anal opening usually separated from the superanal; embryo a glochidium, the soft parts being inclosed in a bivalve shell and borne in the inner or outer or all four leaves of the branchiz. Subfamily UNIONINZE Swainson, 1840. (EXOBRANCIHLE. ) Shell having essentially concentric beak sculpture. Animal with labial palpi somewhat drawn out, projecting posteriorly ; embryos borne in the outer or in all four gills. HETEROGEN. Male and female shells different, the latter inflated in the post-basal region; beak sculpture decidedly doubly looped ; embryos contained in ovisacs separated by a sulcus and occu- pying the hinder part of the outer gills. 2 TRUNCILLA Genus TRUNCILLA Rafinesque, 18109. Truncilla RAFINESQUE, J. de Phys., Chimie, Hist. Nat., LXXXVIII, 1810, p. 427. Shell rounded or oval, solid, inflated, generally smooth and rayed; with delicate beak sculpture, which has a tendency to be doubly looped; that of the female having a very decided inflation in the post-basal region, which is thinner than the rest of the shell, of different texture, often toothed, and usually radiately sculptured; laterals double in each valve, the inner in the right valve smaller. Animal generally having the inner gill united to the abdominal sac; female with a heavy flap of the mantle, which fills the post-basal swelling of the shell, and which has an inner ridge inside at some distance above the edge; marsupium very distinct, occupying the swollen part of the shell. Type: Truncilla triqueter Rafinesque. The species which I have placed in the generic group Trun- cilla though quite devious in form appear to be all rather closely related and to have characters in common, which sep- arate them from all other Naiades. ‘These characters show them to be easily the most highly organized and specialized of all the Unionide. The most striking character of the group is the remarkable difference between the shells of the males and females. This difference consists principally in the unusual development of what I have called the marsupial swelling of the latter, a character totally wanting in the shells of the males. This is always thinner than the rest of the shell, it is very commonly of somewhat different texture, it is inflated on the disk and usually at the base or posterior base, often into a widely rounded wing. In many cases it is marked off from the rest of the shell by sulci in front or behind or both. It is in nearly all cases more or less radially sculptured and toothed at the edge and the remains of these teeth are seen along the growth lines. The shells of male and female are alike at first and as a rule continue so until they are from a TRUNCILLA 3 third to half grown when the peculiar development of the marsupial swelling commences. They become so diverse when adult that it is little wonder that they have in several cases received different names at the hands of expert students. As a corresponding character in the animal of the female the marsupium, which occupies the hinder part of the outer gills, is very distinctly marked off from the rest of the branchiz and is much produced, often resembling a kidney in front, and at- tached to the gill by a narrow band. The mantle js produced into a flap immediately over the marsupium, is often thickened at its border and has a strong, projecting flap within and back from the edge of the outer one. KEY TO SPECIES OF TRUNCILLA. As the male and female shells differ so greatly in most of the species I have thought it best to give keys for each. FEMALE SHELLS. Marsupial swelling large, inflated, rounded, placed at or a little behind the middle of the base. Shell large, marsupial swelling much developed. T. foliata; lewisii. Shell and marsupial swelling of moderate size. T. stewardsoni. Marsupial swelling inflated, extending to near, but not quite to the posterior end of the hase. Shell much inflated, suborbicular or short elliptical, chest- nut or brownish, shining, sculptured behind. T. haysiana. Pale yellow, somewhat elliptical, scarcely sculptured be- hind. T. othcaloogensis. Shell long, quadrate. Greenish, rayed, silky. T. sulcata; personata. Yellowish or brownish, not silky, or but slightly so. T. brevidens ; lenior ; compacta; metastriata. 4 'TRUNCILLA Marsupial swelling inflated, radially sculptured, extending to the extreme posterior base. Raised into a sharp ridge, ending in a sharp point behind, sheli triangular. T. triquetra. Not sharply elevated nor sharp behind. Much flattened below. T. arceformis. Projecting below the base. T. penita. Marsupial swelling thin, compressed or subcompressed, round- ed into a post-basal flap. Swelling enormously produced, dark. T. perplexa. Swelling moderate in size. ; Usually dark. T. propinqua; capseformis. Rarely dark. T. rangiana; biemarginata; deviata; sampsonii. - MALE SHELLS. Shell triangular. Without a radial depression. Much inflated; posterior ridge high. T. triquetra. Moderately inflated; posterior ridge not high. T. compacta; modicella; penita; metastriata. With a radial depression in front of the posterior ridge. T. sampsonit. Very short. : Chestnut-colored, glossy, radially sculptured behind. T. haysiana. Yellow-green, rayed, not sculptured behind. T. personata. Long triangular. T. propinqua. Shell subquadrate or subrhomboid. Without a radial depression. Posterior ridge high, sharp. T. arceformis. Posterior ridge rounded, sides flattened. 7. brevidens. With a radial depression. Depression wide, distinct, deep. T. foliata; lewisu. Depression moderate, not deep. T. stewardsoni. TRUNCILLA 5 Shell subtrapezoid, obliquely truncate below the posterior ridge, base line shorter than dorsal line. Radial depression narrow; beaks far in front. 7. sulcata. Radial depression wide; beaks not at front end. T. sampsonii. Shell irregularly elliptical or oval. With a median row of knobs. T. perplexa. Without knobs. Subsolid. T. capseformis. Solid. With a strong biangulate posterior ridge. T. florentina; biemarginata. Subgenus TRUNCILLA S. S. Shell covered with broken rays, somewhat triangular, and without a wide, radiate, posterior furrow. Group of Truncilla triquetra. Shell greatly inflated, sharply truncate posteriorly ; inflation of the female shell at extreme post-basal point. TRUNCILLA TRIQUETRA Rafinesque. Shell long triangular, much inflated, solid, slightly inequi- lateral; beaks full and high, turned inward and forward over a well-marked lunule; surface with irregular growth lines, the dorsal slope being radially sculptured ; posterior ridge high, angled; epidermis tawny to yellow-green with broken, bright green rays and rows of green mottlings ; teeth subcompressed ; pseudocardinals ragged, there being usually two in each valve ; laterals short, elevated, granular, two in the left valve and one in the right; beak cavities deep; anterior scars deep; nacre white, silvery, thicker in front. Male shell much larger than that of the female, less sharply triangular. Female shell having the marsupial region elevated into a narrowly rounded, radially sculptured ridge, projecting but little below the base. 6 ; TRUNCILLA Length (male) 69, height 48.5, diam. 35 mm. Length (male) 55, height 36, diam. 31 mm. Length (female) 52, height 34, diam. 39 mm. Length (female) 45, height 28, diam. 30 mm. Ohio River drainage; western New York to southern Mich- igan; lowa; eastern Nebraska to Indian Territory. Type locality, Falls of the Ohio. Truncila triqueter Rarinesqur, Ann. Gen. Sci. Phys. Brux., XIII, 1820, p. 300, pl. Lxxx1, figs. 1-4—CHENU, Bib. Conch., rst ser., IE, 1645, ps 15, pl. mes Unio triqueter SHort and Eaton, Transylvania Jl., 1831, p. 79: Truncilla triquetra SIMPSON, Syn., 1900, p. 517. Unio triangularis Barnes, Am. Jl. Sci., VI, 1823, p. 272, pl. xu, fig. 17—Hitpretu, Am. Jl. Sci., X, 1828, p. 287, fig. —Say, Am. Conch., No. 1, 1830, pl. 1v.—REEvE, Conch. Syst., I, 1841, p. 118, pl. Lxxxix, fig. 9—CHENU, Bib. Conch;, ast ser., IT], 1845, Obs., 1X 1803“ p. t4,cpl) xxv, fie: 261. Margaron (Unio) sampsonii Lea, Syn., 1870, p. 40. Truncilla sampsonit Simpson, Syn., 1900, p. 523. This seems to be a smaller species than 7. perplexa, is gen- erally more inflated, is almost entirely without anything like knobs and the shells of both male and female are subquadrate or trapezoid. The species does not seem to be common and it is possible that none of the specimens I have seen are fully adult. ‘TRUNCILLA PROPINQUA (Lea). Shell subtriangular to subelliptical, inflated, solid, very in- equilateral; beaks full and high; lunule wide; posterior ridge rather narrowly triangular; median ridge full; sometimes it 28 TRUNCILLA and the posterior ridge are slightly knobbed ; between the two there is a wide, well-impressed radial furrow, which is deepest in the male shell; surface with decidedly sulcate rest marks; epidermis varying from straw-colored or tawny to yellow- green, feebly rayed, subshining or somewhat silky ; pseudocar- dinals triangular; double in the left valve, single or treble in the right ; laterals curved, strong, double in each valve ; muscle scars small, impressed; nacre bluish-white to straw-color, rare- ly pink. Male shell subtriangular, the deep, radial depression ending in a rather narrow sinus below. Female shell subellip- tical, the marsupial swelling rounded, moderately produced, often darker than the rest of the shell. Length (male) 55, height 40, diam. 33 mm. Length (male) 53, height 45, diam. 33 mm. Length (female) 58, height 47, diam. 32 mm. Length (female) 57, height 43, diam. 33 mm. Tennessee and Cumberland River drainage. Type locality, Florence and Tuscumbia, Ala. Unio propinquus Lea, Pr. Ac. N. Sci. Phila., I, 1857, p. 83; Jl. Ac. N.. Sci. Phila); V, 1862; p.'63, ‘pl “vShio? rae Ops. Var: 1862, p. 67, pl. v, fig. 212——Sowerrsy, Conch. Icon., XVI, 1868, pl. LXxIx, fig. 417. Margaron (Unio) propinquus Lea, Syn., 1870, p. 34. Truncilla propinqua SIMPSON, Syn., 1900, p. 523. Rather more solid and inflated than 7. perplexa, with a deeper, narrower radial impression and having a much less de- veloped marsupial swelling in the female shell. It is rather more in equilateral than perplesa. TRUNCILLA BIEMARGINATA (Lea). Shell subtriangular, subrhomboid or irregularly obovate. solid, but little inflated, inequilateral; beaks moderately full and elevated; posterior ridge decidedly biangulate; median ridge but moderately developed ; the radial depression between the two wide and shallow; growth lines strong and irregular : epidermis yellowish-green, faintly rayed; pseudocardinals tri- angular, two in the left valve and three in the right; laterals double in the left valve, partly double in the right; nacre TRUNCILLA 29 bluish-white to creamy. Male shell with a decidedly biangu- late posterior ridge ending in a biangulation below, the radial depression in front of it wide; female shell somewhat obovate, the radical depression fading out on the rounded, darkened marsupial swelling. Length (male) 46, height 32, diam. 22 mm. Length (female) 36, height 28, diam. 17 mm. Tennessee River drainage. Type locality, Florence, Ala. Unio biemarginatus Lea, Pr. Ac. N. Sci. Phila., I, 1857, p. $3; jieAce Nese. Phila, V1, 1866, p. 47, pl. xvi, fig..45; Obs., Ml 7867) p. 51. pl. xvi, fie. 45. Margaron (Unio) biemarginatus Lea, Syn., 1870, p. 38. Truncilla biemarginata SIMPSON, Syn., 1900, p. 524. Smaller than T. perplexa or T. propinqua, having the pos- terior ridge more decidedly biangulate. TRUNCILLA CAPSAFORMIS (Lea). Shell subsolid, elliptical or irregularly obovate, convex, somewhat inequilateral; beaks moderately full and elevated, their sculpture very feeble ; surface with irregular growth lines ; epidermis yellowish-green with green, rather faint rays; pseu- docardinals small, subcompressed, double in each valve; lat- erals single in the right valve, double in the left ; anterior scars small, impressed ; posterior scars large, shallow ; nacre bluish- white to creamy, thicker in front. Male shell almost evenly elliptical, often with a double posterior ridge and slightly bi- angulate behind. Iemale shell with an enormously developed, rounded, compressed marsupial swelling, which is occasionally toothed a little and is dark green in color and thin. It is fre- quently marked off from the rest of the shell by a sulcus in front and behind. Length (male) 67, height 42, diam. 26 mm. Length (female) 48, height 36, diam. 17 mm. Length (female) 52, height 37, diam. 19 mm. Tennessee River drainage. Type locality, Cumberland River. 30 TRUNCILLA Unio capseformis LEA, Tr. Am. Phil. Soc., VI, 1834, p. 31, pl. u, fig. 4;—Obs., I, p. 143, pl. 11, fig. 4.—Conrap, Monog., VIII, 1837, p. 72, pl. xu, fig. 2, 3—Hantey, Biv. Shells, 1843, p. 19, pl. Xx1, fig. 5.—IXusteR, Conch. Cab. Unio, 1852, p. 44, pl. vu, fig. 5—Rrrve, Conch. Icon., XVI, 1864, pl. xvi, figs. 79, 79a, 79D. Margarita (Unio) capseformis Lea, Syn., 1836, p. 24; 1838, pi 19: Margaron (Unio) capseformis Les, Syn., 1852, p. 27; 1870, Pp. 42. Truncilla capseformis Simpson, Syn., 1900, p. 524. The above measurements of a male shell are from a rather Jarge specimen. I have seen female shells considerably larger than the specimens whose measurements I have given, but they do not often grow larger. The species is less solid than most of the members of the group, the male shell being nearly evenly elliptical and that of the female having a greatly rounded, com- pressed marsupial swelling. It resembles the female of T. per- plexa, but is smaller, thinner, is less rude and lacks knobs. TRUNCILLA FLORENTINA (Lea). Shell irregularly elliptical or obovate, more or less inflated, inequilateral, rather solid; beaks quite full and elevated; sur- face with uneven growth lines; epidermis yellowish-green, feebly rayed; pseudocardinals small, triangular, double in each valve; laterals double in the left valve, single or partly double in the right; anterior scars small, impressed; posterior scars shallow ; nacre bluish-white, thicker in front. Male shell irreg- ularly elliptical, with a decidedly double posterior ridge, which ends in a biangulation behind, with a shallow radial depression in front of it, the ridge in front of this full; female shell with a somewhat produced, rounded, thin, compressed marsupial swelling, usually not darker than the rest of the shell, often toothed and marked off from the rest of the shell by sulci. Length (male) 44, height 32, diam. 23 mm. Length (female) 33, height 26, diam. 18 mm. Tennessee River drainage. Cumberland River. Type localitv, Florence, Ala., and Cumberland River, Tenn. TRUNCILLA 3 Unio florentinus Lea, Pr. Ac. N. Sci. Phila., VII, 1857, p. 83; ete Necscio bila. V5, 1862 5p..64, pl. v, fig, 213; Obs.. V IM 1S62,-p: 68, pl.-v, fg. 203. Margaron (Unio) florentinus Lea, Syn. 1870, p. 42. Truncilla forentina SIMPSON, Syn., 1900, p. 524. Unio turgidulus Lea, Pr. Ac. N. Sci. Phila., II, 1858, p. 40; jiPAceNe.ScrePhilas Vi 1862p: 62, pl: v; fig. 21r;, Obs., VIII, 1862, p. 66, pl. v, fig. 211 —ReEEveE, Conch. Icon., XVI, 1864, pl. xvu, fig. 80. Margaron (Unio) turgidulus Lea, Syn., 1870, p. 42. Unio nux Kuster, Conch. Cab. Unio, 1861, p. 218, pl. Lxxui1, fig. 2. Unio sacculus Reeve, Conch. Icon., XVI, 1864, pl. xv, fig. 67. —AntHony, Am. Jl. Conch., I, 1865, p. 157, pl. x11, fig. 3. Unio saccatus Kuster, Conch. Cab. 1861, p.. 263, pl. LXXxIx, fies 2. So far as I have seen the female shell is smaller than that of the male. The male is more inflated than that of 7. biemar- ginata, the angles of the posterior ridge are not quite so pro- nounced nor is the radial depression so deep. Lea’s Unto turgidulus is the male and his florentinus the female of the same species. TRUNCILLA DEVIATA (Reeve). Shell rather solid, somewhat elongated, more or less inflated, inequilateral; beaks high and full; surface with irregular growth lines; epidermis yellowish-green with numerous, nar- row, feeble rays; pseudocardinals small, rough, subcompressed, two in each valve; laterals single in the right valve and double in the left; anterior scars small, impressed; posterior scars shallow; nacre bluish-white, thinner and iridescent behind. Male shell elliptical or ovate, the posterior ridge scarcely bi- angulate. Female shell with high full beaks, narrowly round- ed in front, with a large, rounded, subcompressed marsupial swelling. which extends considerably below the rest of the basal line and is often radially sculptured and grooved. It is some- times darker than the rest of the shell. 32 MICROMYA Length (female) 39, height 24, diam. 20 mm. Cumberland and Tennessee Rivers. Type locality, Tennessee. Unio deviatus Reeve, Conch. Icon., XVI, 1864, pl. xv, fig. 61. —AntHony, Am. Jl, Conch., I, 1865, p. 156, pl. x11, fig. 2. Margaron (Unio) deviatus Lea, Syn., 1870, p. 42. Truncilla deviata SIMPSON, Syn., 1900, p. 524. Probably distinct from 7. florentina, though it may be but a variety of it. Reeve figured it in the Conchologia Iconica, but his specimen was not characteristic and he credited it to Anthony’s manuscript in Museum Cuming. The next year, 1865, Anthony described it in the American Journal of Conch- ology and gave a characteristic figure of a female shell. The -only male shell I have seen is in the Lea collection, 27 milli- meters long, 19 high, and 13 in diameter, is no doubt young and has the beaks much eroded. The female shells are more elongated than those of florentina, have much fuller, higher beaks and the marsupial swelling is rather more produced. It has been found at Hardy, Arkansas, by Mr. J. H. Ferriss. Unfigured and indeterminate species. Truncilla (Unio) perplexus Ratinesque. Truncilla granulatus Rafinesque. Unio (Truncilla) metaplata Rafinesque. All of these in Continuation of Monog., 1831, p. 4. Genus MICROMYA (Agassiz, 1852) Simpson. Micromya Acassiz, Arch. fur Nat., 1852, p. 57.—ORTMANN, Ann, Car. Mus., VIII, 1912, p. 337. Shell subtriangular oval, solid, dark, feebly rayed with un- dulating lines; beak sculpture almost wanting, consisting of a few feeble, doubly-looped ridges; hinge teeth heavy, laterals club-shaped and truncated posteriorly ; post-basal swelling of the female distinct and often rather abrupt, sometimes some- what irregularly radially ridged, the shell of this part being quite thin. MICROMYA 33 Animal with mantle fringed below, maculate on the border, which is greatly thickened at the post-basal part in the female and developed into a flap, with a distinct, toothed -ridge inside ; marsupium occupying the posterior part of the outer branchiz in numerous distinctly marked ovisacs; inner gill free from abdominal sack in part. Type: Unio fabalis Lea. Ortmann, (1. c.), considers this a subgenus of Eurynia. Group of Micromya fabalis. Shell small, with faint, undulate rays, inflated area of female scarcely radiately striated. MIcCROMYA FABALIS (Lea). Shell small, long ovate or long elliptical, very solid, subin- flated to inflated, inequilateral; beaks somewhat elevated, sub- compressed, pointed, turned forward a little over a well-mark- ed lunule, having doubly-looped, subnodulous sculpture; sur- face with irregular growth lines; epidermis ashy-greenish, wavily rayed with dirty brown or brownish-green; pseudocar- dinals triangular, low, solid, double in the left valve, single, double or treble in the right; laterals heavy, double in the left valve, often partly double in the right ; muscle scars small, im- pressed; nacre white or bluish, iridescent behind, thicker in front. Male shell usually long ovate, subinflated or convex. Female shell generally long elliptical, inflated; the marsupial swelling but slightly inflated, not distinctly marked off from the rest of the shell, placed toward the hinder part of the base and occasionally having vestigial radial wrinkles, thinner than the rest of the shell, and excavated within. Length (male) 38, height 22, diam. 12 mm. Length (male) 30, height 18.5, diam. 14 mm. Length (female) 25.5, height 15, diam. 12.5 mm. Ohio River drainage; Rouge River, mear Detroit; New York. Type locality, Ohio River. 34 MICROMYA Unio fabalis Lea, Tr. Am. Phil. Soc. IV, 1831, p. 86, pl. x, fig. 16; Obs., I, 1834, p. 96, pl. x, fig. 16—CnHeENnu, II]. Conch., 1858, pl. vit, figs. 1, 1a, 1b.—Sowersy, Conch. Icon., XVI, 1866, pl. Xxxv1, fig. 196. Margarita (Unio) fabalis Lna, Syn. 1836, p. 28; 1838, p. 20. Margaron (Unio) fabalis Lea, Syn., 1852, p. 31; 1870, p. 49. Micromya fabalis Simpson, Syn., 1900, p. 525. Eurynia (Micromya) fabalis ORTMANN, Ann. Car. Mus., VIII, IQ12, Pp. 339: Unio capillus Say, Trans. Journ., IV, 1831, p. 528. Unio lapillus Say, Am. Conch., V, 1832, pl. x11; VI, 1834, No. 49.—Conrap, Monog., VI, 1836, p. 54, pl. xxrx, fig. 12.— CuHENU, Bib. Conch., Ist ser. III, 1845, p. 52, pl. xiv, figs. 1, 1a, 1b.—Kuster, Conch. Cab., 1848, p. 53, pl. x1, fig. 3. A very variable species, in size, form and solidity. Some adult male shells are scarcely solid or inflated; others are pon- derous and very full. Usually the female shell is smaller and more inflated than the male. Group of Micromya celata. Shell triangular ovate, with a low, rounded posterior ridge; male and female shell distinctly wrinkled behind. MicromMya C@LATA (Conrad). Shell subtriangular to subovate, very solid, convex to in- flated, inequilateral; beaks high, often subcompressed, turned forward over a small lunule, with feeble, subnodulous sculp- ture; postericr ridge well developed, narrowly rounded; sur- face with irregular growth lines and well-marked rest periods with strong, corrugated, subradial sculpture on the hinder half of the shell, which is divaricate on the posterior ridge and which sometimes covers the entire shell; epidermis clouded, dull green and yellowish-green, feebly rayed, rarely uniform dull green; pseudocardinals low, subradial, ragged, two in the left valve, one to three in the right valve; laterals heavy, double in the left valve, partly double in the right; muscle scars small, impressed; nacre white, silvery, iridescent be- hind, thicker in front. Male shell subovate or subtriangular, LAMPSILIS 35 with a broad, shallow, radial depression in front of the poste- rior ridge, or having the disk at least flattened. Female shell usually ovate, sometimes inflated, smaller than that of the male, with a feebly developed marsupial swelling on the base near the posterior end. This is rougher than the rest of the shell and shows the strong folds within. Length (male) 51, height 35, diam. 21 mm. Length (male) 42, height 33, diam. 17 mm. Length (female) 37, height 25, diam. 20 mm. Length (female) 34, height 25, diam. 14 mm. Tennessee River drainage. Type locality, Elk and Flint Rivers, Tenn. Unio celatus Conrap, Am. Jl. Sci., XXV, 1834. p. 338, ple fige > New FW. Shells, 1834, p.'20; pl. m1, fig. 4>:p. 68.— Cuenu, Bib. Conch., ist ser: III, 1845, p. 16, pl. m1, fig. 3.— REEveE, Conch. Icon., XVI, 1864, pl. u, fig. 7. Margarita (Umo) celatus Lea, Syn. 1836, p. 12; 1838, p. 14. Margaron (Umo) celatus Lea, Syn. 1852, p. 20; 1870, p20. Micromya celata StMpson, Syn., 1900, p. 525. While the shells of this species differ somewhat from those of M. fabalis, it is more in degree than in diversified characters. The latter rarely exhibits even traces of corrugated sculp- ture, yet it is sometimes seen, especially on the marsupial swelling. Mf. celata is generally much higher than M. fabalis, but there are specimens of the females of both species before me that are much alike in outline. Both species are colored much alike and the marsupial swelling, the heavy shell, wide hinge plate, club-shaped laterals and small, deep muscle scars are much alike. The citation of this species from Michigan by Sager and Miles is certainly erroneous. Genus LAMPSILIS Rafinesque, 1820. Lampsilis RAFINESQUE, Ann. Gen. Sci. Phys. Brux., 1820, p. 298.—OrtTMANN, Ann. Car. Mus., VIII, 1912, p. 345. Shell oval to elliptical, smooth or slightly concentrically sculptured, usually without a posterior ridge; epidermis gen- 36 LAMPSIELIS erally smooth and shining, often brilliantly rayed; beak sculp- ture, for the most part, consisting of fine, parallel ridges, which show a tendency to fall into an anterior and posterior loop; hinge with one or two pseudocardinals and one lateral in the right valve, and two pseudocardinals and two laterals in the left; female shell having a moderate and gradual inflation in the post-ventral region opposite the marsupium. Animal hav- ing the inner gills usually attached nearly or quite their entire length to the abdominal sack ; marsupium occupying the hinder part of the outer gills; ovisacs distinct, separated by sulci, rounded below having a fold near their bases, the whole pro- jecting below the inner gills; mantle edge double and thick- ened, often swollen behind into a sort of flap in the female. Type: Unio ovatus Say. The genus Lampsilis contains a large number of North American Uniones of a high type, usually having decidedly dimorphic shells. The marsupium is placed in the hinder part of the outer gills and consists of few to many distinctly mark- ed ovisacs, the whole of somewhat different appearance from the rest of the gill, even when empty. The genus apparently does not rank so high as does Truncilla, as there is not such a remarkable difference between the shells of the sexes. In the female shells of the latter group the marsupial area is gen- erally quite distinctly marked off from the rest of the shell, being thinner, of different texture, often suddenly inflated and radially ridged and toothed. In Lampsilis this area consists of a mere gradual inflation, sometimes quite feeble or hardly perceptible; it is rarely much thinner than the surrounding shell and never toothed or striated or of different texture. The genus seems to be naturally divisible into four groups. Lampsilis typical, Ewrynia, Carunculina and Proptera. 1 can- not be certain what Rafinesque’s Lampsilis cardium is, but it is doubtless a member of the group to which Unio ventricosus, capax and cariosus belong. ‘These species are characterized by inflated, large shells, the male and female being dimorphic, and having coarsely sculptured beaks. Eurynia contains the forms .AMPSILIS 37 with fine, doubly-looped beak sculpture: Carunculina is charac- terized by small, dark shells with singly-looped beak sculpture, and Proptera consists of generally large forms with a dorsal wing and purple nacre. The shells of this genus are never arcuate, even in old age, and never biangulate. The posterior ridge is often wanting, and is seldom high or angulated. KEY TO GROUPS OF LAMPSILIS. Shell without a dorsal wing. Inflated, with coarse beak sculpture. Group of L. ventricosa. Shell solid. Evenly long elliptical, feebly dimorphic, rayed. Gr. of L. ligamentina. Short elliptical, strongly dimorphic, smooth, feebly rayed. Gr. of L. orbiculata. Male shell sinuate at post-base; female shell highest. Gr. of L. trabalis. Small; beak sculpture singly looped. Gr. of L. texasensis. Long elliptical, rayed. Thin, evenly rounded behind; female much swollen at post-base. Gr. of L. modioliformis. Rather solid, thinner behind, beak sculpture irregular. Gr. of L. iris. Long or short elliptical, strongly dimorphic; female shell obliquely truncate behind. Smooth, scarcely rayed. Gr. of L. anodontoides. Scarcely smooth. Gr. of L. subrostrata. Shell long, pointed behind. Very glossy, brightly rayed. Gr. of L. subangulata. Dull colored, feebly rayed. Gr. of L. ellipsiformis. Compressed, elongated, dull colored. Gr. of L. nasuta. Shining, inflated, rayed, dimorphic ; pseudocardinals small. Gr. of L. luteola. 38 L.AMPSILIS Small, obovate, beak sculpture doubly looped. Gr. of L. amygdalum. Shell more or less dorsally winged when perfect. Thin, decidedly gaping in front and behind. Subinflated, dark, shining. Gr. of L. amphichena. Compressed, dull colored. Gr. of L. leptodon. Shell inflated. Thin, beaks smooth, feebly rayed. Gr. of 1. saladoensts. Solid, scarcely dimorphic. Gr. of L. umbrosa. Large, obovate, strongly winged. Strongly dimorphic, shell dark. Gr. of L. alata. Scarcely dimorphic, thin. Gr. of L. gracilis. Shell of medium size. Obovate, bright copper-colored, subinflated. Gr. of L. metallica. Compressed, with a strong dorsal wing. Gr. of L. scutulata. Subgenus LAMPSILIs Ss. Ss. Shell inflated, rather thin, shining, sometimes having a pos- terior ridge; beak sculpture coarse, consisting of a few more or less parallel ridges, which scarcely fall into loops. Animal having the mantle of the female usually toothed and_thick- ened on the post-basal portion, which develops into a large, curious flap when the gills are filled with ova. Type: Unio ovatus Say. LAMPSILIS VENTRICOSA (Barnes). Shell large, rather solid, obovate, inflated, with very full, high beaks, which have a few coarse, irregular corrugations that are inclined to be doubly looped ; surface generally nearly smooth, the rest periods well marked; epidermis normally shining, greenish, greenish-yellow or brownish with broad, bright green rays. In old shells the rays are often nearly or quite wanting. Hinge line usually incurved in front of the beaks and outcurved behind them; ligament large and prom- inent, extending under the beaks, and narrow in front of them. LAMPSILIS 39 There are two, somewhat compressed pseudocardinals in the left valve, one in front of the other, the hinder high and hav- ing a triangular outline, the front lower, and both of these are in front of the beak; the hinge plate is narrow and rounded behind them, and there are two rather short, slender laterals ; right valve with two compressed pseudocardinals, the lower the higher, separated by a deep, nearly parallel-sided socket, and one high, curved lateral, which is sharply truncated behind ; beak cavities deep and wide; muscle scars not deep, smooth, the hinder semicircular; nacre brilliant, silvery, bluish-white or sometimes a beautiful pink. In the female shell the marsupial swelling is pronounced, and the shell is generally higher than that of the male. Length 130, height 90, diam. 60 mm. Entire Mississippi drainage; St. Lawrence system; Nelson River and tributaries. Type locality, Wisconsin River; Mississippi River, Prairie du Chien, Wis. Unio ventricosus Barnes, Am. Jl. Sci. VI, 1823, p. 267, pl. xu, fig. 14 (outline).—Say, Am. Conch., No. IV, 1832, pl. XxXxX1I.—HAantey, Biv. Shells, 1843, p. 180, pl. xxiv, fig. 8. —CHENU, Bib. Conch., 1st ser. III, 1845, p. 45, pl. xu, figs. I, 2—Sowerpsy, Conch. Icon., XVI, 1866, pl. xLiu, fig. 235. Mya ventricosus Eaton, Zool. Text-Book, 1826, p. 221. Margarita (Unio) ventricosus Lea, Syn., 1836, p. 23; 1838, p. 18. Margaron (Umo) ventricosus Lea, Syn., 1852, p. 26; 1870, Oe Lampsilis ventricosus Baker, Moll, Chicago, Pt. 1, 1898, p. 94, pl. xu, figs. 3-5.—SmitTuH, Bull. U. S. Fish Com., 1899, p. 291, pl. LxxXx1II.—SIMPSON, Syn., 1900, p. 526. Lampsilis ventricosa Stimson, Shells of N. Eng., 1851, p. 14. Unio occidens Lea, Tr. Am. Phil. Soc., ITI, 18209, p. 435, pl. x, fig. 16; Obs., I, 1834, p. 49, pl. x, fig. 16—Kuster, Conch. Cab. Unio, 1856, p. 170, pl. 11, figs, 1, 2—CHENU, IIl. Conch., 1858, pl. x11, figs. 5, 5a, 50. 40 LAMPSILIS Margarita (Unio) occidens Lea, Syn., 1836, p. 23; 1838, p. 38. Margaron (Unio) occidens Lea, Syn., 1852, p. 26; 1870, p. 41. Unio subovatus Lea, Tr. Am. Phil. Soc., IV, 1831, p. 118, pl. xvi, fig. 46; Obs., I, 1834, p. 128, pl. xvi, fig. 46.— HAN ey, Biv. Shells, 1843, p. 184, pl. xxu, fig. 43.—CHENU, Ill. Conch., 1858, pl. x11, figs. 6, 6a, 6b.—Sowersy, Conch. Icon., XVI, 1866, pl. xxx1, fig. 163; 1868, pl. Lxxxv, fig. 456. Margarita (Unio) subovatus Lea, Syn., 1836, p. 19; 1838. p- ry; Margaron (Unio) subovatus Lea, Syn., 1852, p. 24; 1870, p. 37: Unio cardiwm Conrap, New F. W. Shells, 1834, p. 68.—Kus- TER, Conch. Cab. Unio, 1856, p. 169, pl. L, figs. 1-4. Unio cardium Raf. v. ocerdens Pare., Conch. Sam., III, 1890, p. 147. Unio cardium Raf. v. ventricosus Pare, Conch. Sam., IIT, 1890, p. 147. i Unio fasciolus Ferussac, Guer. Mag. 1835, p. 26. Unio ovata DesHaAyrs, An. sans Vert., 3d ed., 1839, p. 660. Unio ovatus Kuster, Conch. Cab. Unio, 1852, p. 55, pl. XII. fig. I. Unio lenis Conrap, Monog., XII, 1840, p. 106, pl. vit, fig. 2. Unio canadensis Lea, Proc. Acad. N. Sci. Phila., I, 1857, p. 85; Jl. Ac. N. Sci. Phil., IV, 1860, p. 268, pl. xxiv, fig. 148; Obs., VII, 1860, p. 86, pl. xiv, fig. 148. Margaron (Unio) canadensis Lea, Syn., 1870, p. 37. Unio dolabreformis Sowrersy, Conch. Icon., XVI, 1867, pl- LIX, p. 208. Unio latissimus Sowrrny ?, Conch. Icon., XVI, 1868, pl. LXv1, fig. 337. Barnes only gave outline figures of this species; two of these are of females and one is of a male shell. Lea’s subovatus is a male and his oceidens is a bright colored form. One of his figures of the last is of a female, the other is of a male. I,ea’s U. canadensis appears to be a diseased or depauperate ventn- ILAMPSILIS 4I cosus with a rather strongly developed posterior ridge. He has only the type in his collection and I have never seen any- thing like it elsewhere. Var. satura (Lea). A form rather common in southwestern waters. It is greatly inflated, with livid or smoky-colored, sometimes blackish epidermis, and the marsupial swelling is remarkably developed. It gradually merges into the type. Southwestern States to Sabine River, Texas. Type locality, Alexandria ; Lake Calcashue, New Orleans, Ia. Unio satur Lea; Pr. Am. Phil. Soc., V., 1852, p. 252; Tr. Am. Phil. Soc., X, 1852, p. 205, pl. xvu, fig. 19: Obs., V, 1852, p. 21, pl. xvu, fig. 19 —CuHeENu, Man., 1859, IJ, p. 138, fig. 666.—Sowersy, Conch. Icon., XVI, 1868, pl. xcit, fig. 501. Margaron (Unio) satur Lea, Syn., 1852, p. 24; 1870, p. 37. Lampsilis ventricosus var. satur SIMPSON, Syn., 1890, p. 527. Var. lurida n. v. Throughout the St. Lawrence drainage a form is found, which is generally less inflated than the type, having lurid, ash- colored or smoky epidermis, which is lighter colored on the posterior ridge. This form is generally believed to be Lea’s Unio canadensis and is rayless or feebly rayed, but it is really quite different from the specimen to which the great author gave that name. The form, which I call Jurida, rarely has rays and when they are present they are dark smoky-brown. The typical ventricosa occurs more or less abundantly throughout the St. Lawrence area. LAMPSILIS EXCAVATA (Lea). Shell inflated, subsolid, the male irregularly ovate or rhom- boid, the female obovate, with a high, decided posterior ridge ; beaks high and full; ligament large, brown, extending for- ward in a narrow excavation in front of the beaks; epidermis smooth and shining on the disk, roughened and wrinkled on the somewhat truncated post-slope, tawny or greenish-yellow, showing a few green rays; hinge line with a slight double A2 LAMPSILIS curve, rounded in front of the beaks and out behind them; two pseudocardinals in the left valve, one behind the other, the anterior much the larger, with a triangular outline, both are compressed and situated in front of the beak; there are two small remote laterals and the middle of the hinge plate is narrow and rounded; right valve with two subcompressed, triangular pseudocardinals, the lower the larger, and one high lateral truncated behind; beak cavities deep and wide; muscle scars shallow, smooth; nacre white. The female shell is somewhat inflated at the post-basal outline ; it is not so sharp at the posterior end as is the male shell. In the male shell the posterior point is about one half the distance up from the base to the top; in the female it is a little higher. Length 85, height 65, diam. 50 mm. Tombigbee and Alabama River drainage. Type locality, Othcalooga Creek, Ga. Unio excavatus Lea, Pr. Ac. N. Sci. Phila., IX, 1857, p. 32; Ji. Ac. N. Sci, Phila., 1V;1858, p..71, pl xm, he52; Ons., VI, 1858, p. 71, pl. xu, fig. 52—CuHeEnu, Man., 1859, II, p. 138, fig. 665.—Sowrrsy, Conch. Icon., XVI, 1868, pl. LXXVII, fig. 403. Margaron (Unio) excavatus Lea, Syn., 1870, p. 37. Lampsilis excavatus SIMPSON, Syn., 1900, p. 528. ? Unio ovatus Say var. ornatus ConrAp, Monog., I, 1835, p- 4- Unio ornatus Sowersy, Conch. Icon., XVI, 1866, pl. xx x1, fig. 162. LAMPSILIS BINOMINATA (Simpson). Shell of moderate size, subsolid to rather thin, somewhat inflated, the male irregularly elliptical, the female obovate ; posterior ridge not high, rounded ; beaks only moderately full ; their sculpture consisting of strong, slightly double-looped ridges: epidermis smooth, shining, showing the rest periods, wrinkled on the posterior slope, greenish, yellowish-green or tawny, showing a few narrow, generally sharply defined dark green rays; the teeth are much as in L. excavata, two com- pressed pseudocardinals in each valve, two laterals in the left LAMPSILIS 43 and one thin and truncated one in the right valve; the hinge plate is narrow and rounded in the middle; beak cavities only moderately deep, narrow ; muscle scars rather shallow, smooth ; nacre bluish or purplish-white. The female shell has a well- developed marsupial swelling. Length 45, height 32, diam. 20 mm. Chattahoochee and Flint Rivers, Georgia. Type locality, Chattahoochee River, Columbus, Ga. Unio lineatus Lea, Pr. Am. Phil. Soc., I, 1840, p. 287; Tr. Am. Phil. Soc., VIII, 1842, p. 206, pl. xu, fig. 20; Obs., IIT, 1842, p. 44, pl. xu, fig. 20.—CueEnu, Ill., Conch., 1858, pl. xxviut, figs. I, 1a, tb.—Kuster, Conch, Cab. Unio, 1862, p. 278, pl. xciv, fig. 1.—Sowersy, Conch. Icon., XVI, 1868, pl. LXI, fig. 309. Margaron (Unio) lineatus Lua, Syn., 1852, p. 27; 1870, p. 41. Lampsilis binonunatus Simpson, Syn., 1900, p. 528. This species differs from L. excavata in being smaller and less inflated; its beaks are not so full and high, the post-ridge is lower and more rounded, and the posterior part of the shell is not much wrinkled. Lea’s name was preoccupied by Valenciennes (Encyc. Meth., II, 1827, p. 151, pl. ccxivi, fig. 5) for what is probably Cs radiatus. I changed it to binominatus in the Synopsis. J,AMPSILIS CARIOSA (Say). Shell slightly obovate, rather thin to subsolid, scarcely in- flated, with a moderately developed, rounded posterior ridge; beaks fairly developed, sculptured with a few coarse, parallel ridges, which are sometimes feebly doubly looped, surface smooth and shining, straw-color to tawny, sometimes rayed on the posterior slope ; left valve with two compressed pseudo- cardinals, the hinder low and immediately under the beak, and two delicate, remote laterals; hinge plate rounded in the mid- dle; right valve with one compressed pseudocardinal and gen- erally a small one above it, and a single lamellar lateral, which is truncated behind. Beak cavities only moderately deep; an- terior muscle scars shallow, smooth ; posterior scars faint ; na- 44 LAMPSILIS cre bluish-white, much thinner behind. The female shell has a well-developed marsupial swelling and is generally shorter and higher than that of the male. Length 120, height 80, diam. 45 mm. Length 105, height 63, diam. 35 mm. Atlantic drainage from Georgia to the lower St. Lawrence. Type locality, Delaware and Schuylkill Rivers. Unio cariosus Say, Nich. Encyc., II, 1817, pl. 11, fig. 2.—Con- RAD, Monog., IV, 1836, p. 40, pl. x1x.—Goutp, Inv. of Mass., 1841, p. I11, fig. 72; Binney, Inv. of Mass., 1870, p. 172, fig. 475.—Rerve, Conch. Syst., I, 1841, p. 119, pl. LXXXIX, fig. 10—Dr Kay, Zool. of N. Y., Pt. 5, 1843, p. 193, pl. xx1, figs. 243, 244—HANtey, Biv. Shells, 1843, p. 190, pl. xx, fig. 22—KustTer, Conch. Cab. Unio, 1852, p. 24, pl. 1, figs. 2, 3—Sowrrsy, Conch. Icon., XVI, 1867, pl. Liu, fig. 294.—HarTMAN and MicHENER, Conch. Cest., 1874, p. 38, fig. 183.—Simpson, Naut., VIII, 1895, p. 122, 2 figures. Margarita (Unio) cariosus L&s, Syn., 1836, p. 23; 1838, p. 18. Margaron (Unio) cariosis:-Lma, Syn., 1852, p. 27; 1870, p. 42. Lampsilis cariosus Simpson, Syn., 1890, p. 528. Unio cariosa LAMARCK, An. sans Vert., VI, 1819, p. 80. Mya cariosa Eaton, Zool. Text-Book, 1826, p. 218. Lampsilis cariosa Stimson, Shells of N. Eng., 1851, p. 14. Unio ovatus var. b. LAMARCK, An. sans Vert., VI, 1819, p. 75. Unio ovata VALUNCIENNES, Rec. Obs. Zool. Anat., IT, 1833, p. 226,-pl.'L; figs: 1, 10; 1b, Ze. Unio viridis Ferussac, Guer. Mag., 1835, p. 27. Unio oratus Conrap, Ann. and Mag. Nat. Hist., IV, 1849, p. 301; Jl. Ac. N. Sci. Phila., 1850, p. 276, pl. xxxvu, fig. 6. This species has frequently been confounded with L. ochra- cea Say, with which it is generally associated, but which is really a very different species. It is nearer to L. ventricosa, but is always smaller and more delicate in every way, more compressed and is seldom rayed except on the posterior slope. The specimens referred to this species that are often report- ed from the Mississippi drainage are no doubt L. ventricosa. LAMPSILIS 45 LAMPSILIS ALTILIS (Conrad). Shell rather thin, suboval, ovate or subelliptical, but mod- erately inflated; beaks not prominent; posterior ridge low, rounded, sometimes faintly double, so that the shell is slightly biangulate behind; epidermis straw-color or yellowish-brown to blackish, but smooth and rather shining, feebly rayed or rayless; hinge line with a single or double curve; left valve with two small, somewhat compressed pseudocardinals, one in front of the other, both placed just in front of the beak, and in the specimens seen, rather smooth, and two delicate, re- mote laterals; the central part of the hinge plate rounded; right valve with one pseudocardinal, sometimes with a feeble second above it, and one rather high, truncated lateral; beak cavities moderately deep, compressed; muscle scars smooth, rather shallow; nacre whitish or lurid. Length 55, height 35, diam. 20 mm. Alabama ‘River drainage; Little Red River, Clinton, Arkan- sas? Type locality, Alabama River, Claiborne, Ala. Unio altilis Conrap, New F. W. Shells, 1834, p. 43, pl. u, fig. I, and p. 68.—CuHENUu, Bib. Conch., 1st ser., III, 1845, p. 21, plete tio Margarita (Unio) altilis Lea, Syn., 1836, p. 24; 1838, p. 19. Margaron (Unio) altilis Lea, Syn., 1852, p. 27; 1870, p. 42. Lampsilis altilis Stmpson, Syn., 1900, p. 529. In the few examples I have seen, the umbonal region is so eroded that nothing can be made out regarding the character of the beaks, which are probably not very full or high. The species differs from L. cariosa generally in its darker epider- mis, its smaller and thinner shell, in showing slight biangula- tion behind and in the rather feeble post-basal swelling of the female. Conrad says that the nacre is whitish and iridescent, but all the specimens [I have seen have a lurid nacre, often with a tinge of violet. 46 LAMPSILIS LAMPSILIS DOLABRAEFORMIS (Lea). Shell large, inflated, subsolid, with extremely full, high beaks and a rather decided, sharply angled posterior ridge; elliptical to irregularly obovate, the posterior point rather blunt and situated nearly or quite half way up from the base of the shell; ligament rather large and long, running through for- ward under the beaks and showing in a narrow lunule in front; surface rather smooth, especially in the center of the shell, the growth lines strong and concentrically ridged on the anterior portion, the posterior slope often having a few faint radial ridges and wrinkles: color tawny-brownish, shining; left valve with two compressed pseudocardinals, one in front of the other, the anterior higher and placed just in front of the beak, sometimes these are split up into three imperfect teeth or they may all be united into one long, narrow ridge; there are two rather remote, curved laterals; the hinge line is very narrow and rounded in the center; right valve with two opposite pseu- docardinals, the lower the higher, and one high, lamellar lat- eral sharply truncate behind; beak cavities deep and wide; muscle scars shallow, smooth; pallial line distinct ; nacre white, pinkish or purplish. Length 115, height 80, diam. 55 mm. Savannah, Ogeechee, and Altamaha Rivers, Georgia. Type locality, Altamaha River, Liberty Co., Ga. Unio dolabreformis Lea, Tr. Am. Phil. Soc., VI, 1838, p. 103, pl. xxiv, fig: 113 ;Obs., IT, 1838, p. 103; pl. xxrv, fig--113—— Haniery, Biv. Shells, 1843, p. 189, pl. xx1, fig. 47—CHENU,. Ill. Conch., 1858, pl. xxi, figs. 6, 6a, 6b—Kusrer, Conch., Cab., 1861; pr 170, pl: Li, figs: 5,52: Margarita (Unio) dolabreformis Lea, Syn., 1838, p. 18. Margaron (Unio) dolabreformis Les, Syn., 1852, p. 27; 1870 p. 41. Lampsilis dolabreformis Simpson, Syn., 1900, Pp. 529. A fine species resembling L. capax in some respects, but not so strongly inflated and having a sharper posterior ridge. It bears something the same relation to that species that ovata: does to ventricosa. ‘The marsupial swelling is rather feeble. LAMPSILIS 47 I,AMPSILIS CAPAX (Green). Shell greatly inflated, subsolid, obovate, with an excessively full, high, rounded umbonal region; the beak sculpture consist- ing of very faint, oblique ridges: surface generally smooth and somewhat shining, of a smoky, yellowish or reddish- brown, sometimes a smoky olive-color: rest marks distinct ; ligament moderately long, passing forward under the beaks and appearing in front of them in a rather wide lunule: pos- terior ridge full and rounded ; hinge line very strongly doubly curved ; left valve with a single, sometimes a partially double, pseudocardinal in front of the beak, generally ragged and considerably compressed ; the hinge line is narrow and rounded behind it, and has two small. compressed, distant laterals: right valve with two compressed, ragged pseudocardinals opposite each other, the upper extending back to the beak, and a single, high, thin, decidedly truncate lateral: beak cavities deep and very wide; muscle scars shallow, smooth; pallial line distinct ; nacre bluish-white, pinkish or salmon-tinted. ‘The shells are all full at the posterior base, those of the female but little more inflated in that region than are the males. Length 115, height 80, diam. 70 mm. Lower Ohio River drainage; southwest to St. Francis River, Arkansas; north to eastern Iowa: Elkhorn and Blue Rivers, Nebraska? (Aughey). Type locality, Falls of St. Anthony : Bayou Teche. Unio capax GREEN, Cab. Nat. Hist., II, 1832, p. 290.—COoNRAD,. Monog., IX, 1837, p. 75, pl. xtu.—Kusiter, Conch. Cab. Unio, 1852, pp. 21, 65, pl. xv, fig. 3—Sowerpy, Conch. Icon., XVI, 1866, pl. 111, fig. 274. Margaron (Unio) capax Lea, Syn., 1852, p. 27; 1870, p. 42. Lampsilis capax Smrru, Bull. U. S. Fish Com.. 1899, p. 201, pl. LXxxIv.—Simpson, Syn., 1900, p. 529. Symphynota globosa Lexa, Tr. Am. Phil. Soc., V, 1832, p. 41, pl. 1v, fig. 12; Obs., I, 1834, p. 153, pl. 1v, fig. 12. Margarita (Unio) globosa Lea, Syn., 1836, p. 23. Margarita (Unio) globosus Lea, Syn., 1838, p. 18. Umo globosus HANtry, Test. Moll., 1842, p. 188. 48 LAMPSILIS A species, which seems to be only locally abundant, being found in the Mississippi in considerable quantities at various points in lowa, notably Davenport and the mouth of the Iowa River. It is very much inflated, having the fullest umbonal region of perhaps any Unione known; the hinge line is re- markably curved, the epidermis almost invariably has a smoky hue and is rayless, and the shell gapes at the anterior base and the posterior end. 7 LAMPSILIS OVATA (Say). Shell subrhomboid to elliptical, solid, somewhat inflated, with high, full beaks, which have a few coarse ridges nearly parallel with the growth lines; posterior ridge high and sharp; surface with irregular, rude growth lines; epidermis rather smooth and shining on the disk, somewhat roughened and wrinkled on the posterior slope, straw-color, tawny, pale olive or brownish, rayless or feebly rayed; ligament large and prom- inent; left valve with two somewhat compressed pseudocar- dinals in front of the beak, the hinder the smaller, with two rather short, distant laterals, the middle of the hinge plate narrowed and rounded; right valve with two opposite pseudo- cardinals, separated by a deep, parallel-sided socket, the upper smaller and much compressed, with one remote, high, sharply truncate lateral; beak cavities deep, not wide; muscle scars shallow, smooth, the hinder large, rounded or semilunar ; nacre whitish. The female shell is but slightly inflated in the post- basal region. Length 140, height 95, diam. 55 mm. Ohio River drainage ; Rome, Georgia? Type locality, Ohio River and its tributary streams. Unio ovatus Say, Nich. Encyc., II, 1817, pl. 1, fig. 7—Con- rap, Monog., I, 1835, p. 4, pl. 11—Kuster, Conch. Cab Unio, 1852, p. 22, pl. 1, fig. 2—Sowerpy, Conch. Icon., XVI, 1866, pl. xxx1, fig. 164. Margarita (Unio) ovatus Lia, Syn., 1836, p. 19; 1838, p. 17. Margaron (Unio) ovatus Lea, Syn., 1852, p. 24; 1870, p. 37. Lampsilis ovatus SIMPSON, Syn., 1900, p. 530. LAMPSILIS 49 Umio ovata 1,AMARCK, An. sans Vert., VI, 1819, p. 75.—? VaL- ENCIENNES, Coq. Marines, Biv., 1833, pl. L, figs. 1, Ia, 1b, Ic. Lampsilis ovata Ra¥inesgur, Ann. Gen. Sci. Phys. Brux., V, 1820, p. 208. Mya ovata Eaton, Zool. Text-Book, 1826, p. 218. Ai gha ovata Swainson, Treat. on Mal., 1840, p. 266, fig. 49. This species is characterized by its strong, sharp posterior ridge, which is generally wanting, or low, in L. ventricosa. The only other species of the group which has a similarly de- veloped ridge is L. excavata, which is a smaller, more inflated and usually rayed form with the marsupial swelling more dis- tinctly developed. The name ovatus was used for Unio tumidus Retz, by Lis- ter, Donovan, and others, but as it was called a Mya and the generic name Unio was never used with it, it can stand for Say’s species. L,AMPSILIS OCHRACEA (Say). Shell thin, subinflated, elliptical, with rather full beaks, which are sculptured with a few straight, strong ridges; posterior ridge well developed, and ending in a blunt point about half way up from the base of the shell; epidermis dull, scarcely shining, tawny-brownish, generally lurid or smoky and lamel- lated over the posterior part of the shell, generally feebly rayed; left valve with two rather small pseudocardinals in front of the beaks, which are compressed and often grown together, the anterior the highest, with two thin, remote lat- erals; the hinge line is narrow and rounded at the middle; right valve with two triangular, compressed pseudocardinals opposite each other and separated by a deep, narrow pit, the upper the smaller, and a thin, truncated lateral; muscle scars shallow ; beak cavities moderate; nacre lurid, tinged with red- dish or purplish. Length 115, height 70, diam. 60 mm. Length 80, height 50, diam. 35 mm. Atlantic drainage, from New England to the Ogeechee River, Georgia. Type locality, Delaware and Schuylkill Rivers. 50 LAMPSILIS Unio ochraceus Say, Nich. Encyc., 1817, pl. 11, fig. 8—Conrap, Monog., IV, 1836, p. 37, pl. xvii, fig. 2.—Goutp, Inv. Mass., 1841, p. 112, fig.°74; 1870, p. 173, fig. 476—HANLEy, Biv. Shells, 1843, p. 190, pl. xx, fig. 48?—Dr Kay, Zool., of N. Y., ‘Pt. 5, 1843, p.. 193, pl. LxIx, figs. 237, 238—KustTEr, Conch. Cab. Unio, 1856, p. 163, pl. xivu, fig. 1—Sowersy, Conch. Icon., XVI, 1868, pl. Lx1, fig. 317.—HaArTMAN and MicHENER, Conch. Cest., 1874, p. 30, fig. 184.—Simpson, Nautilus, VIII, 1895, p. 122, fig. Margaron (Unio) ochraceus Lea, Syn., 1852, p. 27; 1870, p. 42. Lampsilis ochraceus SIMPSON, Syn., 1900, p. 530. Mya ochracea Eaton, Zool. Text-Book, 1826, p. 218. Symphynota ochracea Lea, Tr. Am. Phil. Soc., III, 1830, p. 455; Obs. I, 1834, p. 60. Margarita (Unio) ochracea L&A, Syn., 1836, p. 23; 1838, p. 18. Lampsilis ochracea Stimpson, Shells of N. Eng., 1851, p. 14. Unio crocatus Lea, Pr. Am. Phil..Soc., II, 1841, p. 31; Tr. Am. Phils ‘Soc; ViIT;, 1842, .p: 2382 pl.vxxuajiic, 523 (Obsy ie 1842, p. 76, pl. xxi, fig. 52—Cuenu, Il. Conch., 1858, pl. ROCKIT es. GT a: Margaron (Unio) crocatus LEA, Syn., 1852, p. 27; 1870, p. 42. Unio rosaceus Conran, Pr. Acad. N. Sci., Phila., IV, 1849, p. 163: Ji, Awad. N. Sci Phila, I, 1e50,"p.,. 275, pls axons fig. 5. Unio troostensis Sowrersy, Conch. Icon., XVI, 1866, pl. XXXVIII, fig. 210. Unto affinis SowrerBy? Conch. Icon., XVI, 1868, pl. Lxin, fig. 318. . A species which does not seem to be very closely allied to any member of the group unless it may be J. delumbis. Its thinness, the rather sharp posterior ridge, the general smoky tint of the epidermis and the peculiar reddish or violaceous nacre are its principal characters. LAMPSILIS SPLENDIDA (Lea). Shell somewhat elongated, subsolid, greatly. inflated, with very full, high beaks and a strong, rather sharp posterior ridge, LAMPSILIS 51 with generally a faint ridge above it; beak sculpture consisting of strong, nearly straight bars; epidermis slightly concentric- ally wrinkled, yellowish-green to reddish-ash with numerous wide or narrow, faint green rays, scarcely shining. The old shells are sometimes dark brownish and apparently rayless. Female shell with a rather strong marsupial swelling, the male is often a little swollen behind the middle of the base; left valve with two rather small, usually subcompressed, pseudo- cardinals, the posterior at some little distance in front of the beak, and two remote laterals, the lower the larger; hinge line greatly narrowed and rounded under the beaks; right valve with two pseudocardinals, the upper narrow and small, the one lateral truncate behind. Beak cavities deep and wide; pos- terior muscle scars shallow, semicircular; nacre pale lurid vio- let, sometimes bluish. Length (male) 95, height 52, diam. 45 mm. Length (female) 95, height 63, diam. 45 mm. Altamaha and Ogeechee Rivers, Georgia. Type locality, Altamaha River, Darien, Ga. Unio splendidus Lea, Tr. Am. Phil. Sdc., VI, 1838; p. 70, pl. xIx, fig. 61; Obs., II, 1838, p. 70, pl. xix, fig. 61.—KustTer, Conch. Cab. Unio, 1852, p. 55, pl. xu, fig. 2—CuENu, II. Conch., 1858, pl. xvu, figs. 7, 7a, 7b—SoweErRBy, Conch. icon, 2oVl, 1866, -pl. xx x1, fe. 16. Margarita (Unio) splendidus Lea, Syn., 1836, p. 23; 1838, pret: Margaron (Unio) splendidus Lea, Syn., 1852, p. 27; 1870, p. 42. Lampsilis splendidus StMPsoNn, Syn., 1900, p. 531. Unio regularis Sowersy, Conch. Icon., XVI, 1868, pl. xxxtv, fig. 181. A somewhat peculiar and rather variable species. The fe- male shell is higher than that of the male, and more blunt behind. It is probably most nearly related to L. ochracea Say, but does not approach very nearly to anything. 52 LAMPSILIS LAMPSILIS DELUMBIS (Conrad). Shell long ovate, very thin and fragile, ventricose ; ligament margin slightly elevated; anterior side rather narrow; poste- rior margin rounded; epidermis olivaceous, with green rays; umbonal slope rounded; beaks only moderately full; margin of the ligament slope rounded, very oblique; within bluish, highly iridescent ; cardinal teeth lamellar; cavity capacious. Length 54, height 30 mm. Type locality, small streams near Cooper River, South Car- olina. Unio delumbis Conrap, New F. W. Shells, 1834, p. 35, pl. v, fig..3.—CHENU, Bib. Conch., rst ser., III, 1845, p. 18, pl. u, fig. 10. Lampsilis delumbis SiMPSON, Syn., 1900, p. 531. I have never seen this species that I know of, and am some- what uncertain as to its relationships, as Conrad says nothing of its beaks or their sculpture. My description of the species is made up from his description and figure. He gives no meas- urements, but it is probable that his figure is life-size, as are the rest of them in the New Fresh Water Shells, and I have given the measurements of this figure. It is possible that this may belong to the group of L. iris. It looks something like an elongated L. ochracea. LAMPSILIS PEROVALIS (Conrad). Shell rather solid and inflated, obovate rather short; beaks high, but only moderately full, situated about two-fifths of the distance from the anterior to the posterior end; their sculpture consists of strong, slightly doubly-looped ridges ; posterior ridge well developed and ending in a blunt point behind about mid- way up from the base; epidermis greenish-yellow or greenish- tawny, with faint rays, smooth and shining in the middle of the disk, a little wrinkled and duller colored at the ends; left valve with two rather strong pseudocardinals in front of the beak, which are rather solid and slightly compressed, the anterior the higher; there are two short, distant laterals, the lower the LAMPSILIS 53 higher ; a rounded, narrowed hinge plate; and one pseudocar- dinal in the right valve, with a small, narrow one above it, and one rather solid lateral, truncate behind; muscle scars well marked, smooth; nacre silvery. The female shell has a strong- ly developed marsupial swelling. Length 53, height 37, diam. 25 mm. Alabama and Black Warrior Rivers. Type localitv, Alabama River, Claiborne, Ala. Unio perovalis Conran, New F. W. Shells, 1834, p. 43, pl. 1, fig. 2; p. 71—CueEnu, Bib. Conch, 1st ser., II, 1845, p. 21, pl. 1, fig. 2—Kuster, Conch. Cab. Unio, 1861, p. 257, pl. EXKKVII} fig. 2 Margarita (Unio) perovalis Lea, Syn., 1836, p. 24; 1838, p. 19. Margaron (Unio) perovalis La, Syn., 1852, p. 27 ; 1870, p. 42. Lampsilis perovalis SIMPSON, Syn., 1900, p. 531. I have seen specimens of what are undoubtedly this from the type locally and they are close to L. clarkiana and L. do- liaris., It is a little shorter than the former, and is less sharply pointed behind; it is not quite so much inflated as the latter and the marsupial swelling is possibly a little fuller than in either of these species; the texture differs a little from that of the other two. However it is quite probable that they all run together, as the combined differences of the three, so faras. | have been able to examine material, are less than is seen in L. ventricosa. LAMPSILIS CLARKIANA (Lea). Shell becoming very solid when fully adult, long elliptical, with only moderately full, high beaks, rather inflated, with a strong, dark ligament, which scarcely shows in front of the beaks ; surface smooth except at the ends of the shell, shining, the epidermis being greenish-yellow, olivaceous or tawny. sometimes brownish or blackish and having a peculiar smoky, soft tint as if almost waxy, faintly rayed or rayless; posterior ridge well developed and ending rather below the middle of the height of the shell; left valve with two solid pseudocardi- nals in front of the beak : - these are subcompressed when young, 54 LAMPSILIS but solid when the shell is adult; the posterior is triangular ; there are two strong laterals, the lower the heavier; the hinge line is rounded and narrow in the middle; right valve with a heavy pseudocardinal, with a small tooth often behind it and a compressed small one above it; there is a single, strong, trun- cate lateral; beak cavities moderately deep; muscle scars well impressed, smooth; nacre whitish, often salmon in the center of the shell. The female shell is not greatly inflated at the posterior region. Length 85, height 55, diam. 40 mm. Length 65, height 45, diam. 30 mm. Type locality, Williamsport, Tennessee ; also near Columbus, Mississippi; Cahawba and Black Warrior Rivers, Alabama. Unio clarkianus Lea, Pr. Am. Phil. Soc., V, 1852, p. 251; Tr. Am: Phil. Soc.,, X, 1852; (p..273, pl, xxi Ne. 36 7ODs., y, I8s2, p. 20, pl..xx1, fig. 30: Margaron (Unio) clarkianus Lea, Syn., 1852, p. 27; 1870, p. 42. Lampsilis clarkianus Simpson, Syn., 1900, p. 532. Unio spillmanii Lea, Pr. Ac. N. Sci. Phila., XIII, 1861, p. 39; Jl. Acad. N. Sci. Phila., V, 1862, p. 98, pl. xv, fig. 246; Obs., VIII, 1862, p. 102, pl. xv, fig. 246. Margaron (Unio) spillmanti Lea, Syn., 1870, p. 42. When fully matured this has one of the most solid shells of any species in the group. Even the young shells are quite heavy. his solidity, its heavy teeth and the peculiar waxy texture of the shell are its best distinguishing characters. I believe it to be absolutely identical with the Unio spillmani of Lea. The habitat “Williamsport, Tennessee,” given by Lea, is open to doubt. He also gives Georgia or Alabama on the authority of Wheatley and it is found in both of these states. LAMPSILIS GERHARDTII (I,ea). Shell subrhomboid, but slightly inflated, subsolid, with only moderately high beaks; there is a rather long ligament, which runs forward under the beaks and is embedded in front of them in a narrow lunule; posterior ridge well developed, LAMPSILIS 55 rounded, ending near the base of the shell in a rounded point ; surface somewhat concentrically sulcate, shining, with a few narrow rays, greenish-yellow; hinge plate solid; left valve with two rather strong pseudocardinals, the anterior under the beak, more elongated, stumpy, with two sub-remote later- als, the lower a little the larger; right valve with one strong pseudocardinal and a small one above it, with an irregular, low tooth under the beak and one high, truncate lateral ; muscle scars well marked, smooth, the posterior ones round; nacre bluish-wnite, silvery, iridescent behind. Length 70, height 46, diam. 26 mm. Type locality, Chattanooga (river?), Georgia. Also, Shorter, Alabama. Unio serhardiu Lea, Pr. Acad., N. Sei. Phila., VI, 1862,. p. TOSis ileenc. Ne Sci. Phila. V/,. 18623). 208, pl. xx x1, fie. 277 ; Os 1X, 1863; p30; pl: xxx fies. 277. Margaron (Unio) gerhardtu Lea, Syn., 1870, p. 35. Lampsilis gerhardtit SIMPSON, Syn., 1900, p. 532. The only specimen I have seen is a male, and I am not pos- itive whether it would be placed here or in the Juteola group, as the beaks are too badly eroded to give any indication of the beak sculpture. It has some characters like [,. straminea Con- rad. LAMPSILIS MULTIRADIATA (Lea). Shell elliptical or subovate, rather solid, somewhat inflated ; ligament long; beaks not prominent, sculptured with rather coarse, irregular, corrugated ridges, which have a tendency to be doubly looped; posterior ridge low, rounded ; epidermis with very fine, concentric laminz, generally shining, greenish-yel- low with very many wavy rays covering the whole shell ; some- times a number of the green rays are blended together; the umbonal region is generally brownish; left valve with two rather delicate, elevated, sometimes subcompressed, pseudocar- dinals and two short remote laterals, the inner the higher; hinge line rounded; right valve with one high pseudocardinal with a small, compressed one above it, and sometimes a vestige 56 LAMPSILIS of a third behind, and one truncated lateral ; beak cavities mod- erate: muscle scars shallow, smooth; nacre bluish. The female shell has often a decided marsupial swelling. Length (male) 70, height 45, diam. 25 mm. Length (male) 77, height 50, diam. 32 mm. Length (female) 60, height 45, diam. 25 mm. Entire Ohio River drainage; Southern Michigan; New York? (Marshall). Type locality, Ohio. Unio multiradiatus Lea, Tr. Am. Phil Soc., III, 1829, p. 434, pl. rx, fig. 15; Obs., I, 1834, p. 48, pl. 1x, fig. 15 —HANLEy, Biv. Shells, 1843, p. 190, pl. xx1, fig. 10.—CueEnu, Ill. Conch., 1858, pl. xu, figs. 2, 2a, 2b—Sowersy, Conch. Icon., XVI, 1868, pl. LXxx, fig. 5060. Margarita (Unio) multiradiatus Lea, Syn., 1836, p. 24; 1838. p. 19. Margaron (Unio) multiradiatus Lea, Syn., 1852, p. 31; 1870, Pp. 42. Lampsilis multiradiatus Stmpson, Syn., 1900, p. 532. Unio fasciolis. Say, Am. Conch., VI, 1834——Conrap, Mon- ography, III, 1836, p. 26, pl. x1, fig. 2—Kuster, Conch. Cab. Unio, 1852, p. 32, pl. v, fig. 4. Unio perradiatus Lea, Pr. Ac. N. Sci. Phila., IT, 1858, p. 40; jl. Ac. N., Sci... Phila., °V , 1862; p. 66; pl yipais-205 lbs. VII {8625 pp: 70; pl wt, Go. 255, Margaron (Unio) perradiatus Lea, Syn., 1870, p. 37. Unio altilis REEVE, Conch. Icon., XVI, 1865, pl. xx, fig. 109. Unio perovalis Sowrrsy, Conch. Icon., XVI, 1866, pl. Xx xviIl, fig. 200. This species is not very closely related to any other form. Its best distinguishing character is the numerous rays which cover the entire shell except the beaks, which are often brown- ish in well-preserved specimens. LAMPSILIS DOLIARIS (Lea). Shell irregularly elliptical, inflated, subsolid, with moder- ately full, high beaks and a decidedly developed, rounded pos- terior ridge, which is sometimes faintly double and ends in a LAMPSILIS 57 blunt, somewhat drawn out point at the middle of the height of the shell; the disk is rather smooth, epidermis wrinkled in front and behind, greenish-yellow or brownish, somewhat lurid; there are a few narrow or hair-like wavy rays, usually arranged in groups; ligament rather long, scarcely developed in front of the beaks; left valve with two rather stumpy pseu- docardinals, which are scarcely compressed, placed in front of the beak and two short laterals; hinge plate narrowed and rounded for a long distance; right valve with one stumpy pseudocardinal and sometimes a small one above it, with a sin- gle, somewhat truncated lateral behind; muscle scars well im- pressed, smooth; nacre dirty bluish-white, lurid in the cavity of the shell. The female shell is but little more inflated in the post-basal region than that of the male. Both are somewhat ‘angled a little behind the middle of the base. Length 60, height 40, diam. 28 mm. Alabama and Tombigbee drainage. Type locality, Etowah River, Ga. Unio dolaris Lea, Pr. Ac. N. Sci. Phila., XVII, 1865, p. 88; eG. wis Laila, Wil; 1868p, 260, pl. xxx, fig. 75; Obs. “Xi 1860, p. 20; pli xxx, hig. 75. Margaron (Unio) doliaris Laas, Syn., 1870, p. 42. Lampsils doliaris Stmpson, Syn., 1900, p. 533. The best distinguishing characters of this species are the angulation just behind the center of the base, from which there is an almost straight line to the hinder part of the shell, and the almost beak-like posterior point, which is sometimes slightly biangulate. The clustered rays seem to be a fairly constant character. JI am rather doubtful, though, whether it is a valid species. LAMPSILIS BREVICULA (Call). Shell obovate, thin, subcompressed, with a very low, ill-de- fined posterior ridge; beaks rather low ; ligament long, passing under the beaks and appearing in front in a small lunule; sur- face nearly smooth, greenish straw-colored, having a smoky tint, with a few delicate, broken rays on the posterior half; 538 L.AMPSILIS these rays are sometimes scarcely perceptible and at other times they break into crescentic or arrow-head spots; left valve with two delicate, subcompressed pseudocardinals placed just in front of the beak, the anterior generally the higher, and two distant, rather short, delicate laterals, the inner the higher; hinge line narrow and rounded in the middle; right valve with a somewhat compressed pseudocardinal, with a smaller one above it separated by a deep, parallel-sided pit, with often a vestige of another tooth behind, and a single lateral decidedly truncate posteriorly ; beak cavities not deep; muscle scars shal- low, smooth; nacre whitish, purple tinted, buff-colored in the cavity of the shell. The female shell is shorter and higher than that of the male and strongly inflated post-basally, the low posterior ridge ends in a decided point about three-fifths of the way up from the base; the male shell is more blunt or even widely rounded or subtriangulate behind. Length (male) 47, height 27, diam. 17 mm. Length (female) 44, height 31, diam. 15 mm. Type locality, Current River and tributaries, Jack’s Ford, and Big Creek, Shannon Co., Missouri. Also, Arkansas. Unio breviculus Cait, Pr. U. S. Nat. Mus., X, 1887, p. 499, pl. xxvii; Tr: Ac. Nat. Sct, St, Wouish Vi 1ags, pee. XVIL. Lampsilis breviculus SIMPSON, Syn., 1900, p. 533. I cannot be certain as to the relationships of this species. The female is a good deal like a small, very delicate L. cartosa, but the tint of color is softer, especially that of the nacre, which is silvery, and the rays are different. Var. brittsi Simpson. Shell more elongated than the type, with deeper sinus be- hind the marsupial swelling and more distinctly rayed. Lampsilis brittsi Simpson, Pr. Ac N. Sci. Phila., 1900, p. 76, pl. V, ies! a, 2: Lampsilis breviculus var. brittsi SIMPSON, Syn., 1900, p. 533- Quite different from the type but rather variable, and in deference to the opinions of some of our best conchologists I have reduced it to the rank of a variety of brevicula. LAMPSILIS 59 LAMPSILIS BIANGULARIS (Lea). Shell elliptical, obovate or subrhomboid, generally inflated, solid, with rather full but not high beaks, with a high, angled posterior ridge and a lower one above it ending in a biangu- lation at the posterior end a short distance above the base; epidermis smooth and shining in the younger shells, which are greenish-yellow with faint broken dark rays; in the old shells it is dark, often blackish, and somewhat roughened ; ligament large, feebly developed in front of the beaks; left valve with two generally high and somewhat compressed, but sometimes stumpy, pseudocardinals, the hinder under the beak, and two rather distant laterals, the hinge line narrowed and rounded in front of them; right valve with one pseudocardinal with a small one above it, and one high, truncate lateral ; beak cavities rather deep and compressed; muscle scars deep, smooth; nacre lurid, dull bluish, or purplish-white. The female shell has only a slightly developed marsupial swelling. Length 95, height 62, diam. 35 mm. Length go, height 50, diam 37 mm. Tennessee drainage. Type locality, Caney Fork River, Tennessee. Unio biangularis Lea, Pr. Am. Phil. Soc., I, 1840, p. 288. Unio biangulatus Lea, Tr. Am. Phil. Soc., VIII, 1843, p. 197, pl. rx, fig. 8; Obs., III, 1842, p. 35, pl. 1x, fig. 8—-CHENU, Ill. Conch., 1858, pl. xxx, figs. 7, 7a, 7b.—KustTER, Conch. Cab. Unio, 1861, p. 189, pl. Lx, fig. 1; pl. Lx1, fig. 1—Sow- ERPY, Conch. Icon., XVI, 1868, pl. Lxxx, fig. 421. Margaron (Unio) biangulatus Lea, Syn., 1852, p. 38; 1870, ps6: Lampsilis biangulatus SiMPSON, Syn., 1900, p. 533- A very variable species in form, epidermis and solidity. It probably groups here, though its relations are not very close to any other members of this assemblage. It is sometimes difficult to separate specimens of this species from L. perdix, which I have placed in the ligamentina group. 60 LAMPSILIS Subgenus Eurynia Rafinesque, 1820. Furynia Rarinrsgur, Ann. Gen. Sci. Phys. Brux., 1820, p. 297.—OrtTMANN, Ann. Carnegie Mus., VIII, 1912, p. 336. Shell oval to oblong; beak sculpture delicate, doubly looped ; mantle double edged and often toothed below; that of the female sometimes developed into a thickened flap at the post- base. Type, Unio recta Lamarck. Ortmann gives this generic rank with Micromya and Carun- culina as subgenera. A number of the species that I have in- cluded in Eurynia, he considers to belong to his restricted genus. Lampsilis and to Nephronaias. 1 have indicated in the syn- onymy the several species that he refers to Ewrynia and Ne- phronaas. Group of Lampsilis luteola. Shell inflated, shining, generally rayed; beak sculpture often broken, with the posterior loop open behind; pseudocardinals rather small, compressed, smooth inside, and often curved slightly upward. Female shell having a strongly-developed, rounded marsupial swelling. LAMPSILIS LUTEOLA (Lamarck). Shell oblong, solid, subinflated or inflated, rather higher be- hind with moderately full beaks; beak sculpture consisting of exceedingly fine, doubly-looped ridges, the hinder loops which are sometimes turned up behind and sometimes open; rarely the sculpture is a little corrugated or broken; surface with somewhat irregular growth lines, sometimes slightly concen- trically sculptured, the rest periods few and usually well marked; epidermis smooth and shining, generally straw-col- ored, yellowish or greenish-yellow, often becoming brown in old shells, and normally exhibiting bright rays throughout, which may be narrow or wide; ligament long, sometimes show- ing in a narrow lunule in front of the beaks; left valve with two pseudocardinals, which are usually a little compressed, the hinder under the beak, the anterior higher and larger, and. two long, rather near laterals, the hinge plate much narrowed LAMPSILIS 6I at their anterior end; right valve with two pseudocardinals, the lower much the larger, and one lateral, which is sometimes a little truncate behind; muscle scars large, well marked, smooth ; beak cavities rather shallow, exhibiting a row of four or five dorsal scars; pallial line well marked; nacre white, blu- ish-white, straw-colored or pink, usually bright, thicker in front. Female shell with a most decided marsupial swelling, and hav- ing the blunt posterior point somewhat higher up (three-fifths of the height) than that of the male (about half way up), and it is usually more inflated. Length (male) 100, height 60, diam. 40 mm. Length (female) 105, height 57, diam. 50 mm. Entire Mississippi drainage, southwest to the Brazos River, Texas; St. Lawrence drainage, entire Dominion of Canada east of the. Rocky Mountains. Type locality, Susquehanna and Mohawk Rivers. Unio luteola Lamarck, An. sans Vert., VI, 1819, p. 79. Unio luteolus Dx Kay, Zool. of New York, Pt. 5, 1843, p. 190, pl. xx, fig. 241.—HANLEY, Biv. Shells, 1843, p. 192, pl. xxu1I, fig. 16.—SoweRpBy, Conch. Icon., XVI, 1867, pl. Lvu, figs. 293, 293a, 293b.— Cat, Tr. Acad. Sci., St. Louis, VII, 1895, Ds255.P0- Tit Margarita (Unio) luteolus Lea, Syn., 1836, p. 25; 1838, p. 19. Margaron (Unio) luteolus Lea, Syn., 1852, p. 28; 1870, p. 44. Lampsilis luteolus Baker, Moll. Chicago, Pt. 1, 1898, p. 103, pls. x1, XxXxvul, fig. 12—SIMPson, Syn., 1900, p. 534. Umio inflatus BARNES, Am. Jl. Sci., VI, 1823, p. 266. Mva infiata F,vton, Zool. Text-Book, 1826, p. 221. Unio siliquoideus BARNES, Am. Jl. Sci., VI, 1823, p. 269, pl. xl, fig. 150 (outline)—Conrap, Monog., II, 1836, p. 22, pls, He 1. Unio siliquoides Kuster, Conch. Cab, Unio, 1852, p. 30, pl. v, fig. 2. Mya siliquoidea Eaton, Zool. Text-Book, 1826, p. 221. Lampsilis. siliquoidea Stimpson, Shells of New Eng., 1851, p. 14. ‘Unio childrent Hanixy, Biv. Shells, 1843, p. 193, pl. xXxut, fig. 57. 62 LAMPSILIS Unio hydianus Kuster, part, Conch. Cab. Unio, 1861, p. 201, iD. UAViL, Ne Unio distans ANtnHony, Am. Jl. Conch., I, 1865, p. 156, pl. XLT, eae: Unio multiradiatus Sowrerpy, Conch. Icon., XVI, 1868, pl. x1, fig. 306. Unio affinis Sowersy, Conch. Icon., XVI, 1868, pl. Lx1, fig. 307. Var. rosacea (De Kay). Shell smaller and more delicate than the type, generally less brightly colored, often nearly or quite rayless; epidermis brownish or pale greenish-yellow ; nacre white, bluish or rose- tinted. Length 60, height 37, diam. 20 mm. The St. Lawrence and Mackenzie areas. Type locality, Seneca Lake, N. Y. Unio rosaceus Dr Kay, Zool. of New York, V, 1843, p. 192. pL. ce2xrx, fies: 365, 3567 pl: Gen, tie. s57" Lampsilis luteolus var. rosaceus SIMPSON, Syn., 1900, p. 535. One of the most abundant, widely distributed Uniones in the world. It probably extends down the Mackenzie River to near the Arctic Ocean and nearly to the mouth of the St. Lawrence. It does not seem to be abundant in Kentucky or the Tennessee River System. In the southwest it is mostly replaced by the closely allied L. hydiana, which is often taken for this species. The variety rosacea of De Kay has typically a beautiful rose-colored nacre, the color in many cases show- ing through the epidermis, but in a majority of cases this form has a smoky, brownish, bronzy or lurid ash-colored epidermis with feeble rays. So far as I know the variety is found only in the St. Lawrence and northward, but fairly typical speci- mens occur throughout this region. LAMPSILIS SUPERIORENSIS (Marsh). Shell long-obovate, subcompressed, subsolid, without a pos- terior ridge; beaks rather low; ligament prominent, brown; curface covered with irregular, coarse growth lines, sometimes almost sulcate, and having a limited number of faint rays; LAMPSILIS 63 epidermis slightly wrinkled, straw-color or greenish-yellow. Left valve with two small pseudocardinals and two somewhat remote laterals, the former just in front of the beak; right valve with two pseudocardinals, the upper one smaller and compressed, and a single, high, truncated lateral; beak cavities shallow; anterior muscle scars rather deep, posterior scars semicircular ; nacre bluish-white, dull, often with a lurid blotch in the cavity of the shell. Length 58, height 34, diam. 20 mm. Upper Great Lakes region. Type locality, Michipicoten River, north shore of Lake Su- perior. Unio superiorensis Marsn, Naut. Le Dies XG L897) p= los pl 1, es. Lampsilis superiorensis SIMPSON, Syn., 1900, p. 535. Close to Lampsilis luteola and possibly a variety of it, This and I.. borealis form connecting links between L. luteola and L. radiata, though they appear to be as well worthy of spe- cific rank as a large number of our forms. The present species is smaller and rather more compressed than the L. luteola, the texture of the shell is different; it is not so bright and shining as that species and it has a duller nacre. LAMPSILIS BOREALIS (A. I’. Gray). Shell solid, inflated, long obovate, sometimes having a slight posterior ridge; beaks rather full but not high; epidermis hav- ing fine, concentric folds, often wrinkled in front, scarcely shining ; surface with few to many rather feeble, dark greenish rays on a greenish-brown or brown ground; left valve with two stumpy pseudocardinals, the hinder under or a very little forward of the beak, and two rather remote, straight laterals ; right valve with one strong, roughened pseudocardinal, a small, compressed one above it, and one high, subtruncated lateral: beak cavities rather deep and wide, with a few im- pressed dorsal pits ; anterior scars smooth, deep ; posterior scars faint: nacre whitish or bluish-white, dull, often having lurid blotches. ‘The male shell is more elongated, more pointed be- nind than the female, which has a slight swelling just behind 64 LAMPSILIS the center of the base. The shells of both male and female are much thickened in front. Length (male) 72, height 42, diam. 32 mm. Length (female) 63, height 40, diam. 31 mm. Lower St. Lawrence drainage, to Lake Michigan; Lake of the Woods. Type locality, Duck Island, Ottawa River, Ont. Unio borealis A. F. Gray, Tr. Ottawa Field Nat. Club, 1882, P- 53, pl. Lampsilis borealis SIMPSON, Syn., 1900, Pp. 535. This species combines the characters of Lampsilis luteola and radiata. It often closely approaches the form of the for- mer, but is generally more inflated. It has, however, the tex- ture and roughened epidermis as well as much the same color as the latter. I,AMPSILIS RADIATA (Gmelin). Shell long obovate, subsolid, subcompressed ; posterior ridge feeble or wanting; beaks rather sharp but not full or high, with delicate, doubly-looped sculpture ; epidermis concentrically swrinkled, often looped, showing numerous more or less dis- ‘tinct rays on a yellowish or brownish-green ground; the left valve has two pseudocordinals, the hinder under the beak, and two straight laterals; the right valve has two pseudocar- dinals, the upper smaller and compressed, and a single sub- truncated lateral; beak cavities not deep, compressed; muscle scars shallow; nacre bluish-white, sometimes dirty salmon reddish or purplish, dull, somewhat thickened in front. The female shell is shorter than that of the male, it is wider at the posterior end. The male shell is often somewhat drawn out and feebly biangulate. Length (male) 90, height 50, diam. 27 mm. Length (female) 80, height 52, diam. 27 mm. Mya radiata GMELIN, Syst. Nat., 13th ed., 1792, p. 3220.— Woop, Index Test., 2d ed., 1825, p. 12, pl. 11, fig. 2.—Han- LEY, Index Test., 3d ed., 1856, p. 16, pl. 11, fig. 32. Unio radiata L.AMARCK, An. sans. Vert., VI, 1819, p. 73. Lampsilis radiata Stimpson, N. Eng. Shells, 1851, p. 13. LAMPSILIS 65 Unio radiatus SPENGLER, Skriv. Nat. Selsk., V, 1792, p. 3; III, 1793, p. 62.—Conrap, Monog., II, 1836, p. 24, pl. x, fig. 2.—Gou Lp, Inv. of Mass., 1841, p. 110, fig. 73; 1870, p. 170, fig. 474.—KustTer, Conch. Cab. Unio., 1852, p. 29, pl. v, fig. 1.—R«eEveE, Conch. Icon., XVI, 1865, p. 27, pl. xxvu, fig. 139.—HartMAN and Micuener, Conch. Cest., 1874, p. 87, fig. 182. Margarita (Unio) radiatus Lea, Syn., 1836, p. 25; 1838, p. 19. Margaron (Unio) radiatus Lea, Syn., 1852, p. 29; 1870, p. 44. Lampsilis radiatus StMPpsON, Syn., 1g00, p. 535. Unio pictorum tenmus Indiv, etc—CHEMNITz, Conch. Cab., 176; p: 23, pl. 11, fie.,7. Unio virginiana Lamarck, An. sans. Vert., VI, 1819, p. 79.— DELESSERT, Rec. Coq. Lam., 1841, pl. xtr, fig. 4. Unio lineata VALENCIENNES, Enc. Meth., II, 1827, p. 151, pl. CCXLVIII, fig. 5. Unio elongata GoopricH, Ill. Nat. Hist., If, 1829, p. 523, fig. Unio tenebrosus Conrap, New F. W. Shells, 1834, p. 42, pl. VU, fig. 1; p. 72.—CHENU, Bib. Conch., 1st ser., III, 1845, pl. It, fig. 5. Unio melinus Conrap, Monog., XI, 1838, p. tot, pl. Lv, fig. 1. —Sowersy, Conch. Icon., XVI, 1868, pl. Lxxxvur, fig. 467. Unio mellinus Pret, Conch. Sam., III, 1890, p. 159. Unio boydianus Lea, Pr. Am. Phil. Soc., I, 1840, p. 286; Tr. Pun, Pil. SOG; VLE 1643, p; 216, .pl. xvi;-fig: 32); Obss I], 1842, p. 54, pl. xvi, fig. 32—CueENu, Ill. Conch., 1858, pl. XKMLG Hes.2; 20,20. Margaron (Unio) boydianus Lea, Syn., 1852, p. 38; 1870, p. 62. Umio crassus Kuster, Conch. Cab. Unio, 1854, p. 113, pl. XxXI, fig. 5. M va oblongata Woop, Index Test., 1856, p. 199, pl. 1; Supple- ment, fig. 2. Unio obliquiradiatus Reeve, Conch. Icon., XVI, 1865, pl. XxIx, fie S Tr. St. Lawrence drainage; Manitoba; Atlantic region south to North Carolina. Type locality, Virginia. 66 LAMPSILIS Gould reports L. radiata from the north shore of Lake Superior, and there is a shell in the U. S. National Museum from the northwest boundary of Wisconsin, which is probably this species. Var. conspicua (Lea). Shell, subsolid, somewhat rhomboid and elongate, subin- flated; beaks rather full: epidermis decidedly concentrically wrinkled, yellowish to greenish-brown, faintly rayed; nacre straw-colored, buff, salmon or reddish. Length 115, height 67, diam. 40 mm. North Carolina and Southern Virginia. Tvpe localitv, Yadkin River, Salisbury, N. C. Unio conspicuus Lea, Pr. Ac. N. Sci. Phila., II, 1872, p. 156; Jie Ac. N. Ser. Phila, VIII) 1874 sp. s4.opk xi heres Ops SOR 1874. 9. 49. -pl: kL iO. Ser. Lampsilis radiatus var. conspicuus SIMPSON, Syn., 1900, p. 536. A very abundant species distributed throughout nearly the entire Atlantic drainage. It varies greatly in size, form, de- gree of inflation, and solidity, and sometimes approaches so near to luteola that it is well-nigh impossible to separate the two. The texture of the two species is different, the radiata generally having a somewhat roughened epidermis, while that of luteola is usually smooth and bright. The nacre of the latter species is white, of a fine, porcellaneous texture, while that of radiata is dull and sometimes almost lurid. The variety conspicua is quite different from the ordinary manifestation of the species, being solider, more rhomboid and inflated than most specimens of radiata, but there are intermediates, which seem to fully connect the two. I have only seen male shells of the variety. LAMPSILIS HYDIANA (Lea). Shell of moderate size, normally suhsolid but sometimes rather thin, long elliptical, ordinarily much inflated ; beaks full and high, their sculpture delicate, consisting of faint, somewhat corrugated double loops, the hinder open behind; surface smooth and shining, sometimes faintly concentrically sculp- LAMPSILIS 67 tured, greenish, waxy-yellow, beautifully and boldly rayed with green. In some cases the rays are broad and very distinct, in others they are split into numerous fine rays with a wider ray of the ground color between them. Occasional shells are scarce- ly rayed at all. Left valve bearing two sharp, sometimes slight- ly compressed pseudocardinals, and often having a small an- terior lamellar third tooth near the edge of the shell; right valve with two pseudocardinals, the lower the larger ; laterals curved, one in the right valve and two in the left; anterior muscle scars well marked; posterior scars faint; nacre gen- erally rich silvery, though sometimes bluish and lurid brown in the cavity of the beaks. The male shell is somewhat pointed behind about midway up from the base; that of the female is rather blunt behind and decidedly swollen at the post-base. Length (male) 60, height 35, diam. 25 mm. Length (female) 57, height 38, diam. 27 mm. Fastern half of Texas; Indian Territory; Arkansas; east to Alabama. Type locality, Teche River, Ia. Unio hydianus Lea, Tr. Am. Phil. Soc., VI, 1838, p. 14, Peavy nes a4 Obs: LIS 28. p.4i14,1 pl. viele. 114. AN- 1HY, Biv. Shells, 1843, p. 192, pl. xx, fig. 6—Kusver, Conch. Cab. Unio., 1861, p. 201, pl. Lxvit, fig. 2—CHENU, Ill. Conch., 1858, pl. xvit, fig. 3, 3a, 3b; pl. xxrv, figs. 7, 7a, 75.—Sowersy, Conch. Icon., XVI, 1866, pl. xxxvu, fig. 203. Margarita (Unio) hydianus Lea, Syn., 1836, p. 25; 1838, p. 19. Margaron (Unio) hydianus Lea, Syn., 1852, p. 28; 1870, p. 44. Lampsilis hydianus Simpson, Syn., 1900, p. 536. Unio placitus Lea, Pr..Am. Phil. Soc. ,V, 1852, p. 252; Tr. Am. Pins SOC., 1652, p. 279, pl. xx wie, 38 Obs., V,1852, p. 35, pl. xxiu, fig. 38.—Kusrer, Conch. Cab. Unio., 1861, p. 262, pl LXxxvilt, fig. 2: Margaron (Unio) placitus Lea, Syn., 1852, p. 29; 1870, p. 46. A beautiful shell, which is often confounded with L. luteola. It is smaller than the typical form of that species, the epider- mis has a more waxy texture, it is generally more inflated and 68 ILAMPSILIS the pattern of rays is bolder, more distinct, and more brilliant. It seems to replace L.. Juteola in the waters of the southwestern states. The nacre of L. hydiana is scarcely thickened in front, while in /uteola it generally becomes thicker anteriorly. [,AMPSILIS APPROXIMA (Lea). Shell but slightly thickened, long elliptical or long obovate. somewhat inflated ; the surface faintly concentrically sculptured, but shining ; beaks not very high or full; epidermis straw-color, often tawny in the region of the beaks, usually rayless except at the posterior slope, and when there are rays they are al- ways faint; right valve with two pseudocardinals, the upper somewhat compressed and smaller ; left valve with two pseudo- cardinals ; there is one lamellar, curved lateral in the right valve and two in the left; beak cavities rather shallow; anterior mus- cle scars well impressed ; posterior scars large but rather faint; nacre whitish or bluish, sometimes dirty, pale purplish, usually with lurid, bronzy blotches in the cavity of the shell, very slightly thickened in front. Male shell sometimes feebly bian- gulate behind, but not pointed’; female shell considerably swol- len at the post-base and rounded or sub-truncate behind. Length (male) 80, height 47, diam. 26 mm. Length (female) 70, height 57, diam. 26 mm. Southern Louisiana; southern Alabama. Type locality, Red River, Alexandria, La. Unio approximus Lea, Pr. Am. Phil. Soc., IV, 1845, p. 164; Tr Am. Phil) ‘Soc., X; 1848, p..74, pl. v, iig..13% Obs. 0y, 1848, p. 48, pl. v, fig. 13. Margaron (Umo) approximus Lea, Syn., 1852, p. 28; 1870, p- 44. Lampsilis approximus SIMPSON, Syn., [gO0, p. 537- Unio affinis Lea, Pr. Am. Phil. Soc., V, 1852, p. 251; Tr. Am. Phil. Soc., 1855, p. 271, pl. x1x, fig. 26; Obs., V, 1852, p. 27, pl. xrx, fig. 26. Margaron (Unio) affinis Lea, Syn., 1852, p. 27; 1870, p. 42. Lampsilis affinis Stmeson, Syn., 1900, p. 537. LAMPSILIS 69 Extremely close to £. hydiana on the one hand and L. clai- bornensis on the other. It is a rather larger, less inflated spe- cies than hydiana; it is generally thinner and less rayed than that species. The ground color is more yellowish or tawny than in fydiana and the nacre duller and more often blotched. All the specimens I have seen have the beaks so badly eroded that no sculpture is visible. The Unio affinis of Lea is shaped a little differently from approxima and in the Synopsis I con- sidered it a distinct species. Since writing that I have seen additional material that leads me to regard them both as the same. LAMPSILIS CONTRARIA (Conrad). Shell rather small; valves convex, solid, elliptical; beaks not prominent, the sculpture not seen; surface generally smooth and shining; epidermis deep ochraceous, becoming lighter at the border of the shell, with linear, radiating wrinkles in the umbonal region; hinge line regularly curved: pseudocardinals triangular, solid, low, laterals reversed in the type, but normal in specimens seen; nacre pale flesh-color: muscle scars well impressed, small. The male shell is elliptical or elliptic oval, having a rounded point just above the posterior base; the fe- male is nearly regularly rounded and wider behind ; marsupial swelling rounded and but slightly produced. Length (male) 50, height 32, diam. 25 mm. Length (female) 52, height 35, diam. 25 mm. Type locality, Ogeechee River, Georgia. Also Pine Barren Creek, Escambia county, Florida. (mio contrarius Conrav, Pr. Ac. Nat. Sci. Phila., IV, 1840, p. 153; Jl. Ac. Nat. Sci. Phila., I, 1850, p. 276, pl. xxxvu, fig. 7. Lampsilis contrarius SIMPSON, Syn., 1900, p. 537. A species close to L. claibornensis and possibly only a variety of it. It is considerably smaller than that species, is more evenly convex, the posterior point of the male shell is nearer the base than is that of 1. claibornensis, the pseudocardinals are shorter and more stumpy. Since the Synopsis was written I have examined shells from Pine Barren Creek, Escambia 70 LAMPSILIS County, Florida, which agree fairly well with Conrad’s descrip- tion and figure of Unio contrarius, and which [| cannot satis- factorily refer to any other species. LAMPSILIS CLAIBORNENSIS (Lea). Shell solid, elliptical, greatly inflated when old, beaks scarce- ly elevated or inflated, their sculpture not seen; surface slightly concentrically sculptured but rather smooth, varying from greenish straw-color to tawny-brown, sometimes having a few faint rays on the posterior slope; the rest of the shell is gen- erally rayless; lunule scarcely developed; left valve with two rather small pseudocardinals and two strong laterals, the low- er the larger; right valve with two pseudocardinals, the upper the smaller and one strong lateral; muscle scars well impressed ; beak cavities moderately deep; nacre bright silvery, sometimes pink or salmon-tinted, a little thicker in front. Male shell somewhat pointed behind about midway up from the base; fe- male shell but slightly produced in the post-basal region, gen- erally nearly rounded behind. Length 70, height 45, diam. 35 mm. Length 7o, height 50, diam. 42 mm. Gulf drainage of the United States, from the Flint to the Pearl River. Type locality, Alabama River, Claiborne, Ala. Unio claibornensis Lwa, Tr. Am. Phil. Soc., VI, 1838, p. 105, pl. xxiv, fig. 115; Obs., II, 1838, p. 105, pl. xxiv, fig. 115.— TroscHEL, Arch. fiir Naturg., V, 1839, pl. 1, p. 237—Han- LEY, Biv. Shells, 1843, p. 192, pl. xx1, fig. 26—CneENu, III. Conch., 1858, pl. xxi, figs. 3, 3a, 3b>—Sowersy, Conch. leon, XV 1, 868, pl? tx: fie: 357. Margarita (Unio) claibornensis L&A, Syn., 1838, p. 19. Margaron (Unio) claibornensis Lea, Syn., 1852, p. 28; 1870, p. 44. Lampsilis clatbornensis SIMPSON, Syn., 1900, Pp. 537: Unio obtusus Lea, Pr. Am. Phil. Soc., I, 1840, p. 287; Tr. Am. Phil. Soc., VIII, 1843, p. 201, pl. x1, tig. 13; Obs., TIT, 1842, p. 39, pl. xt, fig. 13.—CHENU, Ill. Conch. 1858, pl. xxx1, figs. 2, 2a, 2b.—ReEEvE, Conch. Icon., XVI, 1865, pl. xxvi, fig. 129. LAMPSILIS fai Margaron (Umio) obtusus Lea, Syn., 1852, p. 39; 1870, p. 62. Umo pallescens Lea, Pr. Am. Phil. Soc., IV, 1845, p. 164; Tr. igen SOC. %, 1649,.p. 7) pl. vil, fig. 20; Obs., IV, 1848, p. 79, pl. vu, fig. 20. Margaron (Unio) pallescens Lia, Syn., 1852, p. 27; 1870, p. 43. A solider shell than either Lampsilis hydiana or L. approx- ima. It is more inflated than the latter and is never rayed like the former. There are individual specimens, which are intermediate and seem to more or less connect the three species. ILAMPSILIS PERPASTA (Lea). Shell obovate, solid, greatly inflated, with moderate beaks and a rounded posterior ridge, which is somewhat double and ends in a faint, narrow, biangulation at a considerable distance above the base line of the shell; ligament brown, carried for- ward under the beaks and ending in front in a small lunule; growth lines rather rude, irregular; epidermis shining tawny, brownish at the beaks, rayless; left valve with two stumpy pseudocardinals, the hinder opposite the beak, and two re- mote, heavy laterals, the lower the solider; hinge line rounded in the middle; right valve with one principal pseudocardinal and a smaller one in front and behind it ; beak cavities moder- ately excavated; muscle scars deep, smooth; nacre whitish, tinted with lurid purple behind. Length 50, height 35, diam. 28 mm. Length 55, height 42. diam. 35 mm. Type locality, Coosa River, Alabama. Also Swamp Creek, Georgia. Umo perpastus Lea, Pr. Ac. N. Sci., Phila.; V, 1861, p. 60; jieAceN. sem Phila. “Vv, 1862) py 69, pl. vir, fig. 2195 Obs., Vilie1862; pe 73. pli vii, fig. 219. Margaron (Unio) perpastus Lea, Syn., 1870, p. 43. Lampsilis perpastus SIMPSON, Syn., 1900, D. 532. Since writing the Synopsis I have had an opportunity of seeing quite a number of shells of this rare species. In that work I placed it in the ventricosa group, but I am now in- 79 LAMPSILIS clined to believe that it should go in the luteola group, near L. claibornensis. The epidermis is tawny and of a somewhat waxy appearance; the shell is short, solid, and, in old speci- mens, much inflated. ILAMPSILIS PORPHYREA (Lea). Shell elliptical, much inflated, solid, slightly gaping at the anterior base; beaks in the specimens seen apparently low, but badly eroded; growth lines irregular; surface rather smooth, but dull colored, tawny, becoming brownish near the beaks; left valve with two rather small, solid pseudocardinals and two short, heavy, remote laterals ; right valve with three pseu- docardinals, the middle one the largest, the hinder one small, and one strong lateral; beak cavities shallow; muscle scars well impressed; nacre deep purple or dirty white, blotched in the cavity of the shell. Length 56, height 46, diam. 26 mm. Length 46, height 27, diam. 23 mm. Cahawba and Coosa Rivers, Alabama. Type locality, Coosa River, Ala. Unio porphyreus Lea, Pr. Ac. N. Sci. Phila., V, 1861, p. 60; Jl. Ac. N. Sci. Phila., V, 1862, p. 80, pl. x, fig. 228; Obs., VIII, 1862, p. 84, pl. x, fig. 228. Margaron (Unio) porphyreus Lea, Syn., 1870, p. 41. Lampsilis porphyreus Simpson, Syn., 1900, p. 538. Two shells are in the Lea collection, the larger of which is distorted at the anterior base and has a dirty white, blotched nacre. One additional shell with purple nacre has been exam- ined, which belongs to the Aldrich collection. The species is smaller than L. claibornensis, is more solid, more evenly ellip- tical and is slightly biangulate behind in the three specimens examined, which are probably males. LAMPSILIS STRAMINEA (Conrad). Shell long elliptical or long obovate, not greatly inflated, subsolid, with a slight posterior ridge; beaks not full or high, their sculpture not seen; surface usually sculptured LAMPSILIS 73 with strong concentric ridges, rather shining, buff, straw-col- ored or greenish-yellow, often having faint rays on the pos- terior slope, and sometimes a few faint ones on the body of the shell; each valve having two pseudocardinals, the upper one in the right being compressed and smaller; left valve with two lamellar laterals; right valve with one lateral; beak cavi- ties moderately deep; anterior muscle scars impressed; pos- terior scars faint; nacre bluish-white, rather dull, often with a dark spot in the region of the beak cavities, scarcely thick- ened in front. Male shell pointed behind, about midway up from the base; female shell often much produced at the pos- terior base, rounded or subtruncate behind, Length (male) 80, height 50, diam. 30 mm. Length (female) 70, height 50, diam. 30 mm. Southern Alabama, southern Mississippi. Type locality, small streams in southern Alabama. Unio stramineus Conrap, Am. Jl. Sci., XXV, 1834, p. 339, pl. 1, fig. 6; Monog., X, 1838, p. g1, pl. L, fig. 1—Hantery, Biv. dhells, 1843, p. 209, pl. xxi, fig. 45——SoweErBy, Conch. Icon., XVI, 1866, pl. xxxr1x, fig. 217 ; 1868, pl. Lx xx, fig. 422. Margarita (Unio) stramineus Lea, Syn., 1836, p. 39; 1838, p. oe Margaron (Unio) stramineus Lea, Syn., 1852, p. 28; 1870, p. 35: ' Lampsilis stramineus SIMPSON, Syn., 1900, p. 538. The shell is of rather light structure and the concentric sculpture is almost always well developed. Frequently the con- centric ridges are very strong and regular. LAMPSILIS BRACTEATA (Gould). Shell elliptical, thin to subsolid, somewhat inflated, with a scarcely perceptible rounded post-ridge; beaks not elevated, sculptured with rather fine, distinctly doubly-looped ridges; erowth lines irregular; surface either smooth or irregularly sulcate, somewhat shining, greenish straw-colored with nu- merous irregular, wavy, narrow and broad rays; left valve 74 LAMPSILIS with two equal, delicate pseudocardinals and two curved, lamellar laterals; right valve with two pseudocardinals, the lower the larger, and one lateral; beak cavities not deep; nacre bluish, white or salmon-tinted, brilliant, scarcely thickened in front. The male shell is somewhat oblong, and is not narrowed at the anterior or posterior ends, the hinder end rounded and scarcely ‘pointed ; the female shell is somewhat rounded behind and has an evenly curved marsupial swelling. Length (male) 53, height 32, diam. 18 mm. Length (male) 58, height 35, diam. 22 mm. Length (female) 50, height 33, diam. 21 mm. Llanos, Guadalupe, and Colorado Rivers, Texas. Type locality, Llanos River, Texas. Unio bracteatus GouLtp, Pr. Bost. Soc. N. Hist., V, 1855, p. 288. Margaron (Unio) bracteatus Lea, Syn., 1870, p. 43. Lampsilis bracteatus SIMPSON, Syn., 1900, p. 543. I had only seen a single specimen of this species when the Synopsis was written, a male shell presented to Dr. Lea by Dr. Gould, and I was inclined to believe that it was a rather delicate member of the ligamentina group. A considerable amount of material received since then including a number of female shells leads me to believe that it belongs nearer to L. powellii and reeviana. It is a shorter shell than either of these, and the male is more evenly oblong. I,AMPSILIS REEVIANA (Lea). Shell subsolid, but quite thin and inclined to crack at the edges, long, elliptical or long obovate, only moderately inflated ; beaks not high or full, their sculpture not seen; surface smooth and shining, yellowish-green or greenish-yellow, with numer- ous broken, wavy green rays. These rays are often wide and narrow alternately and are so broken as to have occasional concentric bands of the lighter color; hinge with small and sometimes imperfectly developed pseudocardinals, two in the left valve and one in the right; laterals small and short, remote from pseudocardinals and separated from them by a_nar- LAMPSILIS 75 row, rounded hinge plate ; beak cavities not deep; muscle scars shallow ; nacre bluish, a little thicker in front, generally dark in the cavity of the shell. Male shell bluntly pointed or sub- biangular behind midway up from the base; female shell con- siderably produced at the post-basal region, subtruncate or rounded behind. Length (male) 70, height 40, diam. 25 mm. Length (female) 67, height 42, diam. 26 mm. Louisiana ; Texas; Arkansas. Type locality, Alexandria, Ja. ; Unio reevianus Lea, Tr. Am. Phil. Soc., X, 1852, p. 272, pl. xx, fig. 28; Obs., V, 1852, p. 28, pl. xx, fig. 28.—KusrTer, Conch) Cab. Unio; 1861, p= 247, ple X%xxill, fie, 2, Margaren (Unio) reewmanus Lea, Syn., 1852, p. 28; 1870, p. 44. Lampsilts reevianus SIMPSON, Syn., 1900, p. 538. The relationships of this species are a little doubtful, but the character and texture of the nacre are much like those of L.. radiata. It has characters like some of the species of the lig- amentina group. Its exceedingly small, often feebly developed pseudocardinals and remote laterals and the peculiar color pattern are good characters, as well as the color of its nacre. JLLAMPSILIS POWELLII (Lea). Shell long, elliptical or long obovate, subsolid to rather thin, subinflated, narrow and rounded in front, with a few irregular growth lines; beaks only moderately full, their sculpture not observed ; surface tawny, rayless in all the examples seen ; hinge line quite evenly curved; left valve with two rather small, sharp pseudocardinals and two short, remote laterals; right valve with two pseudocardinals, the upper the smaller, and a single rather long lateral; beak cavities moderately deep ; anterior muscle scars impressed, posterior scars large, indis- tinct ; nacre dirty whitish, becoming dark and lurid in the cen- ter of the valves, scarcely thickened in front. Male shell feebly biangulate behind midway up from the base; female shell somewhat produced at the posterior base, wide and rounded behind. 76 LAMPSILIS Length (male) 80, height 47, diam. 28 mm. Iength (female) 75, height 48, diam. 28 mm. Salina and Clinton, Arkansas; Guadalupe River, Texas; Spring River, Kansas (Cragin). Type locality, Saline River, Ark. Unio powellu Lea, Pr. Am. Phil. Soc., V, 1852, p. 252; Tr. Aan. Phil. S0c., 3 1653, PY 27e, ol ois, we, 25. tops nee 1852, p. 26, pl. x1x, fig. 25.—Muscrave, Phot. Conch., 1863, pl. 11, fig. 8—Sowerpy, Conch. Icon., XVI, 1868, pl. Lxx, fig. 359. . Margaron (Unio) powellu Lea, Syn., 1852, p. 28, 1870, p. 44. Lampsilis powellii Stmpson, Syn., 1900, p. 538. This species is close to L. reeviana and is perhaps only a variety of it. It is a little solider than that species, especially at the edges of the shell, is rayless, and has a somewhat differ- ent texture. Group of-Lampsilis orbiculata. Shell elliptical, subquadrate or ovate, very solid, more or less inflated, slightly gaping at the anterior base; beaks well in front, large, full and high, their sculpture consisting of faint, scarcely looped ridges ; epidermis tawny to dark. smooth, scarcely showing rays; lunule deep and distinct, passing under the beaks; hinge and teeth strong; there are two pseudocar- dinals in the left valve and two to three in the right; two lat- erals in the left valve and one in the right; muscle scars well impressed; nacre bright. Animal with large gills, which are rounded below, inner much the larger, united their whole length to the abdominal sac; palpi large, thick, oblique, oval; branchial opening very large; anal opening rather large, both having many small papillee. LLAMPSILIS ORBICULATA (Hildreth). Shell somewhat inflated with a well-marked posterior ridge, elliptical, solid, gaping at the anterior base; beaks moderately elevated, with very faint sculpture; lunule elongated, surface generally having wide, low, concentric ridges, the rest periods LAMPSILIS Th often marked by a sulcus, tawny to pale, dirty olive, sometimes feebly rayed; ligament large and full; left valve with two tri- angular pseudocardinals and two strong laterals; right valve with two pseudocardinals, the hinder triangular and large, the anterior small, there is sometimes a third small pseudo- cardinal behind the other two, there is one strong high lateral ; posterior muscle scars large, rather deep ; anterior scars very deep and rough; beak cavities deep; nacre white or salmon- tinted. The male is pointed behind about midway up from the base ; the female shell has a well-developed post-basal swelling. Length (male) 85, height 70, diam. 34 mm. Length (female) 75, height 63, diam. 35 mm. Ohio and Cumberland Rivers ; west to the Mississippi River. Type locality, Muskingum River, Ohio. Unio orbiculatus Hizprersu, Am. Jl. Sci., XIV, 1828, p. 284.— Han ey, Biv. Shells, 1843, p. 192, pl. xx1, fig. 2—KusTER, Conch. Cab., 1861, p. 216, pl. Lxx1, figs. 3, 4.—SOWERBY, Conch. Icon., XVI, 1866, pl. xiiv, fig. 239. Margarita (Unio) orbiculatus Lea, Syn., 1836, p. 25; 1838, p. 19. Margaron (Unio) orbiculatus Lea, Syn., 1852, p. 28; 1870, Dp. 43- Lampsilis orbiculatus Simpson, Syn., 1900, p. 540. Lampsilis orbiculata OrtMANN, Ann. Car. Mus., VIII, 1912, P- 353- Unio abruptus Say, Am. Conch., No. II, 1831, pl. xvi1,— CuEnu, Bib. Conch., 1st ser., III, 1845, p. 24, pl. vi, figs. 1, 1a, 1b. Unio cyclips Frrussac, Guer. Mag., 1835, p. 28. Unio crassus Conrad, Monog., IV, 1836, p. 34, pl. XVI. Lighter colored, less inflated, and more humped than L. hig- ginsii, the latter having much the form of Obovaria ellipsis Lea. It is lighter colored and more humped, it has a stronger posterior ridge and is less convex than the form I have called higginsii var. grandis. The young shell of orbiculata is more elongated and the beaks are less elevated than is the case in. 78 LAMPSILIS higginsii. Nevertheless the three forms are very puzzling and there are occasional specimens, which cannot be assigned with much certainty to any of the three. LAMPSILIS HIGGINSII (Lea). Shell solid, inflated, gaping at the anterior base, oval, ellip- tical or subquadrate with a feeble posterior ridge, with full, high beaks placed well forward, whose sculpture consists of very feeble, scarcely looped ridges, in front of which is a well-de- veloped lunule ; ligament large; surface with occasional irreg- ular growth lines but generally smooth and somewhat shining ; rest lines dark and usually well marked; color, olive with occa- sional faint rays; left valve with two triangular, short pseudo- cardinals and two heavy laterals; right valve with two, often three pseudocardinals, the middle one the largest, and one lateral, often having a vestige of another below it ; muscle scars deep; beak cavities moderate; nacre silvery, flesh-color or sal- mon-tinted. ‘lhe male shell is bluntly pointed behind about midway up from the base; the female is truncated behind and has a very much-produced marsupial swelling at the extreme posterior base. Length (male) 75, height 60, diam. 42 mm. Length (female) 70, height 60, diam. 40 mm. Ohio River, west to Iowa, and southwest to Kansas. Type locality, Muscatine, Ia. Unio higginsti Lea, Pr. Ac. N. Sci. Phila., IX, 1857, p. 84; JI. Ac. N. Sci. Phila., V, 1862, p. 188, pl. xxiv, fig. 258; Obs., IX, 1863, p. 10, pl. xxiv, fig. 258—Sowerpy, Conch. Icon., XVI, 1868, pl. Lxxxxu, fig. 431. Margaron (Unio) higginsii Lea, Syn., 1870, p. 41. Lampsilis higginsti StMPSON, Syn., 1900, p. 540. Var. grandis n. v. Shell higher and longer than the type, less inflated, that ef the female more produced at the posterior base, color pat- tern generally more brownish, the umbonal region umber- colored, LAMPSILIS 79 Length (male) 98, height 70, diam. 42 mm. Length (female) 76, height 63, diam. 40 mm. Illinois ; Iowa; Kansas; Missouri? Ohio River? This is a very puzzling form, the type seeming to connect with the variety, and there are specimens, which seem to stand between the variety and orbiculata. I have seen perhaps a dozen or more specimens, which are fairly typical, and in these the shell is smaller and more inflated than in the variety, and the epidermis is olive and not darker on the beaks as it is in the form I have called grandis. I found the variety fairly abundant in the Illinois River near Utica: the typical form, which is a rather rare shell, seems to be most abundant in the Mississippi River in the vicinity of Davenport, Iowa. Group of Lampsilis ligamentina. Shell solid, short, evenly elliptical, not greatly inflated, with a vellowish-green epidermis, with broad, usually broken, dark green rays; beaks not prominent, sculpture fine, restricted in area; pseudocardinals rather small, stumpy; nacre silvery or rarely pinkish. The female shell is not greatly swollen in the post-basal region. I,AMPSILIS LIGAMENTINA (Lamarck). Shell solid, almost regularly long elliptical, rounded in front, rounded slightly or pointed behind about midw ay up from the base of the shell, young and adult specimens moderately in- flated, old specimens decidedly swollen, having a low, rounded posterior ridge, slightly gaping at the anterior base: old shells having a well-developed lunule running through under the beaks; beaks scarcely inflated, low, their sculpture consisting of very faint, doubly-looped, irregular ridges ; ligament large, long; surface nearly smooth or marked with rude, irregular, low, concentric ridges, tawny to pale greenish with broad, rather faint and somewhat broken rays; left valve with two small pseudocardinals and two remote, rather small laterals: right valve with two pseudocardinals, the anterior smaller, and sometimes a small posterior third tooth, with one high 80 LAMPSILIS lateral; beak cavities not deep; muscle scars large, well im- pressed and smooth; nacre white or pink, much thickened in front in old shells; female shells very slightly produced at pos- terior base. Length 140, height 90, diam. 58 mm. Mississippi River drainage generally; southern Michigan; western New York; Manitoba; Ontario. Type locality, Ohio River. y Unio crassus Say, Nich. Encyc., II, 1817, pl. 1, fig. 8—Hrp- rETH, Am. Jl. Sci., XIV, 1828, p. 278, fig. 1.—SoweErsy, Conch. Icon., XVI, 1866, pl. x1, fig. 220. Margarita (Unio) crassus Lea, Syn., 1836, pl. 24; 1838, p. 19. Mya crassa Eaton, Zool. Text-Book, 1826, p. 217. Unto ligamentina LAMARCK, An. sans Vert., VI, 1819, p. 72. Unio ligamentinus Kuster, Conch. Cab. Unio, 1852, p. 23, pl. Int, fig. 3.—Cat, Tr. Ac. Sei St Louis, Vil, p22, ph KT: Margaron (Unio) ligamentinus Lea, Syn., 1852, p. 28; 1870, Pp. 43: Lampsilis ligamentinus BAKrr, Moll. Chicago, Pt. I, 1898, p. 108, pl. xv1,—SmiTH, Bull. U. S. F. Com., 1899, p. 291, pl. LXXIX.—SIMPSON, Syn., 1900, p. 539. Nephronajas ligamentina OrtMANN, Ann. Car. Mus., VIII, LOT. pe ae 5: Unio ellipticus Barnes, Am. Jl. Sci., VI, 1823, p. 259, pl. xIll, fig. 19 (outline). Mya elliptica Eaton, Zool. Text-Book, 1826, p. 219. Unio carinatus Barnes, Am. Jl. Sci., VI, 1823, p. 259, pl. x1, fig. 10. Mya carinata Eaton, Zool. Text-Book, 1826, p. 220. Unio ellipsarius Say, Am. Conch. VI, 1834. Unio fasciatus Say, Am. Conch., VI, 1834.—Conrap, Monog., 1835, p. 3, pl. 1—Potiez and Mrcuaup, Gall. Moll., 1844, p. 153, pl. ivi, fig. 5.—Kustrr, Conch. Cab., 1852, p. 31, pl. y, fig. 3. Mya gravis Woop, Ind. Test., (Hanley) 1856, p. 199, pl. 1, fir. 50, LAMPSILIS 8I Unio gravis Pa'reL, Conch. Sam., III, 1890, p. 154. Unto luteolus Sowersy, Conch. Icon., XVI, 1867, pl. tvut, fig. 293a. Unio delodontus Sowersy, Conch. Icon., XVI, 1867, pl. vu, fig. 288. Unio crassidens SoweRBy, Conch. Icon., XVI, 1868, pl. Lxu, fie. 312- Unio pictus SowERBy, Conch. Icon., XVI, 1868, pl. Lxu, fig. a1. Unio venustus SowrRsy, Conch. Icon., XVI, 1868, pl. Lxiv, fig. 326. Unio upsoni Marsu, Conch., Ex. 1, 1887, p. 51. Unio pinguis Lua, Pr. Ac. N. Sci. Phila., I, 1857, p. 84; Jl. Ac. N. Sci. Phila., IV, 1858, p. 78, pl. xv, fig. 58; Obs., VI, 1858, p70, pl: xv, fig? 58. Margaron (Unio) pinguis Lea, Syn., 1870, p. 44. Lampsilis pinguis SIMPSON, Syn. 1900, p. 540. After again carefully comparing the type of Lea’s Unio pinguts, the only specimen I have ever seen, I am quite certain that it is a somewhat peculiar shell of 1. ligamentina, in which the hinge line is a little injured, so that it has become sinuous. The following is a description of the type: Shell irregularly obovate, rather solid, inflated, with a low, rounded posterior ridge; ligament large and long, brownish; beaks rather full, turned slightly forward; in front of and be- between them there is a wide, deep lunule ; surface having occa- sional, irregular, low, concentric ridges, yellowish-green with a few pale rays; hinge line decidedly sinous; left valve with two sharp, somewhat ragged pseudocardinals and two lamellar laterals; right valve with two opposite pseudocar- dinals, the upper tthe smaller, and one high lateral; beak cavities rather deep; anterior scars deep, separate; posterior scars shallow; nacre whitish, iridescent behind with lurid blotches in the cavity of the shell, scarcely thickened before. Length 70, height 48, diam. 33 mm. The shell *gapes decidedly at the anterior base, and the de- pressed lunule makes a deep impression on the dorsal outline. 82 LAMPSILIS Var. gibba Simpson. Shell considerably shorter and more solid than the type, with a decided, curved posterior ridge, the dorsal region much rounded or humped; surface having strong, low, concentric ridges; muscle scars smaller than in the typical shell; female shell somewhat produced at post-base. Length 95, height 70, diam. 40 mm. Ohio River, and southward. Unio crassus Sowervy, Conch. Icon., XVI, 1868, pl. xcv, fig. 520. Lampsilis ligamentinus var. gibbus Simpson, Syn., 1900, p. 540. Var. nigrescens n. v. Shell much elongated, subelliptical to subrhomboid ; epider- mis dark brown to blackish, almost or quite destitute of rays. Length 115, height 61.5, diam. 44 mm. Length 113, height 60, diam. 38 mm. Allegheny County, Pennsylvania; Mississippi River, Le: County, Iowa; Kankakee River, Illinois. A greatly elongated form with very dark, almost or quite tayless epidermis. It seems to be sufficiently distinct to be worthy of a varietal name. Lampsilis ligamentina is an abundant, widely distributed and variable form, generally of large size, and often quite ponder- ous. There are, however, occasional shells of considerable size and light structure. South of the Ohio River and west into southern Missouri and Arkansas the type is generally replaced by the variety gibba, which in many cases is distinct enough to be entitled to specific rank, but the two, forms are connected by many intermediates. Some specimens of the variety ap- proach L. orbiculata in form, but it is a rougher shell, greener colored, and usually has strong, low, concentric ridges. The name crassus was applied to this species by Say before that of Lamarck was given to it, but Retzius had previously used the same name for an European Unio. LAMPSILIS 83 LAMPSILIS TaNIATA (Conrad). Shell moderately convex, long elliptical, rather solid, with scarcely elevated beaks, which are sculptured with distinct, somewhat corrugated, doubly-looped ridges; sometimes these ridges are greatly broken up; surface having more or less scattered growth lines, often concentrically sculptured in front, greenish-yellow, with broad, distinct, broken rays; lunule very narrow ; left valve with two equal-sized, prominent, slender pseudocardinals and two compressed, small laterals ; right valve with one elevated pseudocardinal, sometimes with a vestigial one above it, and one compressed lateral ; beak cavities shallow ; muscle scars well impressed; nacre bluish-white. Male shell bluntly pointed or feebly biangulate behind about half way up from the base; female shell with a moderate, wide marsupial swelling and ending behind in a blunt point two-thirds of the way up from the base. Length (male) 80, height 60, diam. 30 mm. Length (female) 70, height 45, diam. 26 mm. Tennessee and Cumberland River systems. Type locality, Flint River, Morgan Co., Ala. Umo teniatus Conrav, New F. W. Shells, 1834, pp. 26, 72, pl. Iv, fig. 2——Kusrer, Conch. Cab. Unio, 1862, p. 271, pl. xci, fig. 4. Margarita (Unio) teniatus Lea, Syn., 1836, p. 24; 1838, p. 19. Unio taniatus Payret, Conch. Sam., III, 1890, p. 169. Lampsilis teniatus SMPson, Syn., 1900, p. 541. Unio menkianus Lea, Tr. Am. Phil. Soc., V, 1836, p. 76, pl. XIX, fig. 59; Obs., II, 1838, p. 76, pl. xrx, fig. 590.—HANLEY, Biv. Shells, 1843, p. 191, pl. xx11, fig. 4—CHENU, III. Conch., 1858, pl. xix, figs. 4, 4a, 4b.—Kusrer, Conch. Cab. Unio, 1861, p. 245, pl. Lxxxu1, fig. 3—Reeve, Conch. Icon. XVI, 1865, pl. xxvim, fig. 140. Margarita (Unio) menkianus Lea, Syn., 1838, p. 10. Margaron (Unio) menkianus Lua, Syn., 1852, p. 27; 1870, p. 43. 84 LAMPSILIS Unio pulcher Lea, Tr. Am. Phil. Soc., VI, 1838, p. 6, pl. 111, fig. 6; Obs., II, 1838, p. 6, pl. 1, fig. 6—Hantey, Biv. Shells, 1843, p. 193, pl. xxu, fig. 7—CHeENu, Ill. Conch., 1858, pl. xvul, figs. 2, 2a, 2b.—Kuster, Conch. Cab. Unio, I861, p. 193, pl. LXI, gs 5. Margarita (Unio) pulcher Lua, Syn., 1836, p. 25; 1838, p. 19. Margaron (Unio) pulcher Lea, Syn., 1852, p. 28; 1870, p. 44. Unio interruptus Lea, Tr. Am. Phil. Soc., VI, 1838, p. 15, pl. vi, fig. 15 ; Obs., II, 1838, p. 15, pl. vi, fig. 15.—HaAn ey, Biv. Shells, 1843, p. 191, pl. xx1, fig. 28—CueENu, Ill. Conch., 1858, pl. xvi, figs. 4, 4a, 4b. Margarita (Unio) interruptus Lea, Syn., 1836, p. 24; 1838, p. 19. Margaron (Unio) interruptus Lea, Syn., 1852, p. 27; 1870, p. 43- Unio latiradiatus Conrav, Monog., XI, 1838, p. 96, pl. Liu.— Kuster, Conch. Cab. Unio, 1861, p. 208, pl. Lx1x, fig. 3. Unio tennesseensis Lea, Pr. Am. Phil. Soc., I, 1840, p. 288; Tr. Am. Phil. Soc., VIII, 1843, p. 199, pl. x, fig. 11; Obs., III, 1842, p. 37, pl. x, fig. 11—Cuenu, Ill. Conch., 1858, pl. XXVII, figs. I, 1a, 1D. Margaron (Unio) tennesseensis Lea, Syn., 1852, p. 27; 1870, Pp. 43: Unio perdix Reeve, Conch, Icon., XVI, 1864, pl. xvin, fig. 82. The young shells are often brilliantly printed, and the rays are either entire or broken. Old shells become duller colored and are sometimes badly worn. The species probably lives in rapids. After a careful study of all of the above so-called species I cannot see that they possess any characters that make them worthy even of varietal names. LAMPSILIS PICTA (Lea). Shell elliptical or obovate, subsolid, compressed, with flat- tened but sharp-pointed beaks, which have irregular, corrugat- ed, somewhat doubly-looped sculpture ; posterior ridge scarcely developed; above it is a wide, shallow, radial depression end- LAMPSILIS 85 ing in a slight sinus; growth lines fine and rather even ; surface dull to shining ; pale greenish-yellow with much broken rays, forming a concentric row of square spots around the upper part of each season’s growth: lunule small, narrow; let valve with two small, nearly equal, erect pseudocardinals and twe delicate, straight laterals ; right valve with one pseudocardinal and a minute tooth in front of and another behind it, with a single lamellar lateral: beak cavities quite shallow, with a row of small dorsal scars: muscle scars well impressed; nacre silvery or lurid. The female shell seems to differ but little from that of the male: it has a wide, slight marsupial swelling ; both are rounded or feebly biangulate posteriorly. Length 60, height 38, diam. 15 mm. Type locality, Harpeth River, Tennessee. Umo pictus Lea, Tr. Am. Phil. Soc., V. 1834, p. 73, pl. x1, fig. 32; Obs., I, 1834, p. 185, pl. xr, fig. 32-—-Han ey, Biv. Shells, 1843, p. 191, pl. xxi, fig. 35.—KusteEr, Conch. Cab. Unio, 1861, p. 249, pl. txxxit, fig. 5. Margarita (Unio) pictus Lea, Syn., 1836, p. 24; 1838, p. 10. Margaron (Unio) pictus Lea, Syn., 1852, p. 27; 1870, Dp. 43 Lampsilis pictus Stmpson, Syn., 1900, p. 542. Eurynia (Micromya) picta ORtTMANN, Ann. Car. Mus.. Wouule IQI2, p. 342. Unio lindsleyi Lea, Pr. Ac. N. Sci. Phila., IV, 1860, p. 306; jd: Ac. N. Sci. Phila., 1860, p. 351, pl. tv, fig. 176; Obs., VIII, 1860, p. 33, pl. Lvitr, fig. 176.—Sowerpy, Conch. Icon., XVI, 1866, pl. xxir, fig. 2330. Margaron (Unio) lindsleyi Lass, Syn.., 1870, p. 43. Unio camelopardalis Sowrrsy, Conch. Icon.. XVI, 1866, pl. XL, fig. 233a. Very close to teniata, and it may be only a variety of that, but it is more compressed, more evenly rounded posteriorly, and the color pattern is quite different, consisting of square blotches—broken rays—arranged in concentric rows at the be- ginning of each year’s growth. The type, a larger shell than Lea’s largest specimen, is prebably in the Troost collection. 86 LAMPSILIS Lea's shell is perhaps not adult. U. lindsleyi Lea is, I believe, the same thing, but Lea’s shells are older, a little solider and slightly more inflated. LAMPSILIS CAMELOPARDILIS (Lea). Shell long elliptical or long rhomboid, subsolid, with subin- flated valves, rounded in front, with a low, rounded posterior ridge, rounded at the basal part of the posterior end and obliquely truncate above; beaks only moderately full, not ele- vated, their sculpture not seen; surface smooth, shining, pale greenish-yellow, with broad, broken rays, which generally form a series of distinct, square spots, one concentric row on each season’s growth; left valve with two equal, rather high sub- compressed pseudocardinals, the posterior one under the beak, and two short, straight laterals; right valve with a single pseudocardinal, with a vestigial tooth in front of it and an- other behind it, and one lateral; muscle scars well impressed ; nacre bluish-white. The female shell is more evenly rounded behind and is less truncate on the upper part of the posterior end than the male. The latter is slightly rounded on the base; it has a feeble, widely rounded post-basal inflation, and is straight or faintly incurved on the base. Length (male) 60, height 30, diam. 16 mm. Length (female) 55, height 27, diam. 16 mm. ‘l'ennessee and Cumberland River systems. Type locality, Northern Alabama. Unio camelopardilis Lea, Pr. Ac. N. Sci. Phila., IV, 1860, p. 92; Jl. Ac. N. Sci. Phila., IV, 1860, p. 355, pl. 11x, fig. 180; Obs., VIN; 1860; p-737, pl Likes. Tee: Margaron (Unio) camelopardilis La, Syn., 1870, p. 53. Lampsilis camelopardilis Stmeson, Syn., 1900, p. 542. Unio fucatus Lea, Pr. Ac. N. Sci. Phila., IV, 1860, p. 92; Jl. Ac. N. Sci. Phila., IV, 1860, p. 353, pl. 11x, fig. 178; Obs., VIII, 1860, p. 35, pl. 11x, fig. 178. Margaron (Unio) fucatus Lea, Syn., 1870, p. 43. LAMPSILIS 87 Close to I. picta, and L. teniata. I have only seen a few specimens of what are probably young shells of this species. It is less elliptical than either of the other species, is more rhomboid and smoother, the epidermis is a waxy, greenish-yel- low. L,AMPSILIS PUNCTATA (Lea). Shell long obovate, generally solid, subinflated, with low, not inflated beaks, whose sculpture is unknown; posterior ridge low and rounded, sometimes double and ending in a faint bian- gulation ; posterior point about midway up from the base; sur- face covered with rather fine, irregular growth lines; scarcely shining, dirty greenish-yellow with numerous wide or narrow, somewhat broken rays; left valve with two nearly equal, small, erect, slender pseudocardinals and two short laterals; right valve with one pseudocardinal, sometimes with a small one above it; muscle scars well impressed; beak cavities shallow ; nacre white, dirty white or bluish, slightly thicker in front. Both male and female shells are somewhat obovate and full in the post-basal region, but the female is most produced at that point. The shells are generally solid and inflated, but old specimens are much more so. Length (male) 57, height 35, diam. 21 mm. ' Length (male) 76, height 50, diam. 33 mm. Length (female) 52, height 37, diam. 22 mm. Tennessee River drainage. Type locality, Caney Fork, Tenn., and Tuscumbia, Ala. Umo punctatus Lea, Pr. Ac: N: Sei. Phila., 1X,..1865, p. 89; ji oXe Nee acto bila. Wij 1668..p 261, pl; xxxi- fie. 76; Obs.,; XII, 1860, p. 21, pl. xxx11, fig. 76. Margaron (Unio) punctatus Lea, Syn., 1870, p. 43. Lampsilis punctatus Simpson, Syn., 1900, p. 542. Though evidently related to 1. picta and its allies, this species is quite distinct from all others. The shell is rather neat, the nacre is thick to its edge, and the sides slope very rapidly to the border. 88 LAMPSILIS LAMPSILIS PERDIX (Lea). Shell large, long elliptical, moderately solid, subinflated, with a well-developed posterior ridge; beaks rather full, their sculp- ture not observed; surface with irregular growth lines, decid- edly concentrically ridged in front, nearly smooth at the mid- dle of the shell, roughened on the posterior slope, dirty yellow- ish-green or tawny, generally marked with faint, wide, broken rays; left valve with two equal-sized, erect pseudocardinals and two remote, small, short laterals; right valve with one very high pseudocardinal, a smaller one in front and some- times a vestigial one behind it and one rather high, short lateral; muscle scars very large, well impressed; beak cavities rather deep; nacre bluish-white to creamy, silvery, with a wide prismatic border, thickened in front. The male shell does not differ greatly from that of the female, the latter being a little more rounded behind, and having a slight, wide marsupial swelling. Both male and female shells gape slightly at the anterior base. Length 155, height 100, diam. 60 mm. Tennessee and Cumberland River systems. Type locality, Harpeth River, Tenn. Unio perdix Lea, Tr. Am. Phil. Soc., V, 1827, p. 72, pl. x1, fig. 31; Obs., I, 1834, p. 184, pl. x1, fig. 31 —Hantey, Biv. Shells, 1843, p. 188, pl. xx, fig. 20.—Sowersy, Conch. Icon., XVI, 1868, pl. LXIx, fig. 82. Margarita (Unio) perdix Lea, Syn., 1836, p. 23; 1838, p. 18. Margaron (Unio) perdix Lea, Syn., 1852, p. 26; 1870, p. 41. Lampsilis perdix Simpson, Syn., 1900, p. 542. Nephronajas perdix OrtMANnn, Ann. Car. Mus., VIII, 1912, Ts, 320: Unio pectorosus Conrap, New F. W. Shells, 1834, p. 37, pl. vi, fig. i; p. 713 Monog:, ITT, 1836, -p:'25; pl = he. 1 Han ey, Biv. Shells, 1843, p. 189, pl. xx1, fig. 22.—CHENU, Bib. Conch., 1st ser., III, 1845, p. 19, pl. 11, fig. 8—KusTEr, Conch. Cab. Unio, 1852, p. 26, pl. 1v, fig. 2. Margarita (Unio) pectorosus Lea, Syn., 1836, p. 23; 1838, Pp. 18, LAMPSILIS 8g A large, rather coarse species, which bears some resemblance to L. biangularis. It is rather more compressed and thinner at the edges than L. ligamentina. It has very wide prismatic border. LAMPSILIS VENUSTA (Lea). Shell irregularly long elliptical, solid, subinflated, with rather compressed but pointed beaks, which are sculptured with fine, distinct, doubly-looped ridges ; with a low posterior ridge ; with irregular growth lines; greenish-yellow with narrow and wide, somewhat broken, wavy rays; left valve with two equal, erect pseudocardinals and two straight laterals ; right valve with one pseudocardinal and a small one above it, with one lateral and sometimes a vestige of another below it; beak cavities shallow ; nacre white, scarcely thickened in front. Both male and female shells are full at or behind the middle and somewhat narrowed at the ends. Both are bluntly pointed behind, that of the male midway up from the base, that of the female a little higher up. There is a feeble marsupial swelling just behind the center of the base. Length 57, height 32, diam. 21 mm. Type locality, Potosi, Missouri. Unio venustus Lea, Tr. Am. Phil. Soc., W288 38.. p45) pls 15, fig. 4; Obs., II, 1838, p. 4, pl. 11, fig. 4 Hantxy, Biv. Shells, 1843, p. 192, pl. xx111, fig. 5—CuHeEnu, Ill. Conch., 1858, pl. SOME, fies. 7, 1a, 1b. Margarita (Unio) venustus Lea, Syn., 1836, p. 24; 1838, p. 19. Margaron (Unio) venustus Lua, Syn., 1852, p. 27; 1870, p. 43. Iampsilis venustus StmPson, Syn., 1900, p. 543. In some respects this shell approaches 1. ellipsiformis, in others it has characters of the ligamentina group. I hardly know where to place it. There are specimens, which seem close tO 47958) Group of Lampsilis anodontoides. Shell elongated, inflated, moderately solid, sharply pointed behind ; that of the female much produced at the posterior base, behind which it is diagonally truncate; epidermis very bright, go LAMPSILIS smooth and shining, but feebly rayed; beaks not prominent, marked with very delicate, regular sculpture, the posterior loop often open behind; pseudocardinals smooth, generally com- pressed; nacre shining, white or purplish. Animal having the marsupium very distinct and well rounded below; inner edge of the mantle usually beautifully and evenly toothed behind. L,AMPSILIS ANODONTOIDES (Lea). Shell large, elongated, with dorsal and ventral lines nearly parallel, rounded in front, pointed behind, more or less inflated, solid; beaks rather full but not high, their sculpture consisting of numerous, distinct ridges looped in the middle but open be- hind; posterior ridge low and rounded; surface smooth and shining, but often having concentric growth ridges in front, tawny to pale straw-color, sometimes with a few rays on the posterior slope, the rest of the shell generally rayless; there is often a large, brown flush in the umbonal region; ligament large and long; left valve with two subcompressed pseudocar- dinals, the hinder somewhat elongated, and two long, nearly straight, delicate laterals; right valve with two pseudocardi- nals, the upper faint, and one lateral; beak cavities not deep; muscle scars rather large, well impressed ; nacre white, cream- colored, salmon-tinted or pink, slightly thicker in front. Both male and female shells end behind in a point two-thirds of the way up from the base; the female shell has a large, rounded marsupial swelling and is slightly incurved at the central base. Length (male) 127, height 62, diam. 45 mm. Length (female) 120, height 62, diam. 45 mm. Entire Mississippi River drainage except (probably) the up- per Missouri. All the Gulf drainage from the Withlacoochee River, Florida, to the Rio Grande, and into Mexico. Type locality, Mississippi, Alabama and Ohio Rivers. Unio anodontoides Lua, Tr. Am. Phil. Soc., IV, 1834, p. 81, pl. vin, fig. 11; Obs., I, 1834, p. 91, pl. viii, fig. 11—CHENU, Ill. Conch., 1858, pl. xrv, figs. 3, 3a, 3b.—Reeve, Conch. Icon., XVI, 1865, pl. xrx, fig. 87—Simpson, Proc. U. S. Nat. Mus., XV, 1892, p. 430, pl. Lxx1, fig. 7, pl. Lx x11, figs. I, 2, 4. LAMPSILIS gt Margarita (Unio) anodontoides Lea, Syn., 1836, p. 35; 1838, p. 24. Margaron (Unio) anodontoides Lea, Syn. 1852, p. 36; 1870, p. 58. Lampsilis anodontoides Baker, Moll. Chicago, Pt. I, 1898, p. 100, pl. x, figs. 1, 2.—Smiru, Bull. U. S. Fish Com., 1899, p. 200, pl. Lxxvit.—Srmpson, Syn., tgoo, P. 543.—ORTMANN, Ann. Car. Mus., VIII, 1912, p. 346, fig. 25. Unio teres Say, Am. Conch., VI, 1834.—Conrab, Monog., VI, 1836, p. 52, pl. xxviir—Kuster, Conch. Cab. Unio, 1854, p. OS; pil xviIiigss 1,. 4. Var. floridensis (I,ea). Shell smaller, thinner, less inflated and in every way more delicate than the type, sometimes with a few faint rays; teeth more compressed ; female shell narrowed in front and having the marsupial swelling more near to the center of the shell and more elongated than in the type. Length (male) 85, height 41, diam. 26 mm. Length (female) 63, height 33, diam. IQ mm. Southern Alabama and Georgia to central Florida. Type locality, Choctawhatchee River, W. Fla. Unio floridensis Lea, Tr. Am. Phil. Soc., X, 1852, p. 274, pl. XXI, fig. 31; Obs., V, 1852, p. 30, pl. xx1, fier, Margaron (Unio) floridensis Lea, Syn., 1852, p. 39; 1870, p. 62. Lampsilis anodontoides var. floridensis SIMPSON, Syn., 1900, p. 544. An abundant, widespread, variable form. The variety flori- densis is smaller, generally lighter, and more delicate in every way than the type; the marsupial swelling is not placed so near to the posterior end and the front end of the shell is often narrower. It extends north into southern Georgia, and delicate specimens are found along the Gulf Coast into Texas. At Mier, Mexico, a rather short variety is found. The species is solider, larger and higher in proportion than L. fallaciosa, is not quite so inflated as that species, and is gen- 92 LAMPSILIS erally less rayed, There are occasional specimens of the va- riety that are feebly rayed. I have no doubt but that Lea included in his description both anodoitoides and fallaciosa, for he says that the shell is some- times almost cylindrical and again that “in some specimens, the arcuation of the basal margin is so great that it might almost be taken for a malformation.” But his figure shows the heavy, higher, unicolored, larger shell, that of a female, with rather solid pseudocardinals and we are therefore compelled to accept this for his species. I,AMPSILIS FALLACIOSA (Smith) Simpson. Shell elongated, the hinge and ventral lines nearly parallel, subceylindrical, subsolid, generally inflated; beaks full but not high, their sculpture numerous, distinct, fine ridges looped up in the center, open behind; ligament long, brown, rather nar- row ; anterior end rounded; posterior part ending in a rather sharp point more than midway up from the base of the shell; surface very smooth and glossy, slightly concentrically ridged at the anterior end; color greenish-yellow or yellowish-green, often faintly rayed and always darker on the posterior slope. Left valve with two high, compressed pseudocardinals and two delicate, nearly straight, laterals; right valve with two pseudocardinals, the upper smaller and more compressed and one lateral ; beak cavities moderate; muscle scars well impress- ed; nacre white, straw-colored or salmon-tinted. Length (male) 90, height 37, diam. 32 mm. Length (female) 90, height 40, diam. 33 mm. Upper Mississippi drainage ; south to the Cumberland River, Tennessee, and to Arkansas; Red River of the North? Unio anodontoides Rrrve, Conch. Icon., XVI, 1865, pl. Xx1, fig. 97. Lampsilis anodontoides Baker, Moll. Chicago, Pt. 1, 1898, pl. Xi fie: Unio oriens SoweRsBy, Conch. Icon., XVI, 1868, pl. xu, fig. 314. LAMPSILIS ; 93 Lampsilis fallaciosus Smiru, Bull. U. 5. Fish Com., 1899, p. 291, pl. Lxx1x.—Simpson, Pr. Ac, N. Sci., Phila., 1900, p. 74, pl. 11, fig. 5; Syn. 1900, p. 544. This has generally passed for the true anodontoides, and there are occasional specimens, which stand so completely be- tween the two that they can only with difficulty be referred to either. The L. fallaciosa never reaches the dimensions of anodontoides, it is thinner, more delicate in every way, more inflated as a rule and the hinge teeth are more compressed. As a general thing it is not as high in proportion as anodon- toides and the posterior point is more drawn out, and this lengthening behind is especially noticeable in the male shells. The fallaciosa is generally tinted with green, it sometimes is all green, and it is far more likely to be rayed than its con- gener. This species often has a dark flush at the umbonal region, and I have seen specimens of both it and anodontoides, in which the burnt brown covered the whole shell. LAMPSILIS VIRESCENS (Lea). Shell long elliptical or long obovate, subinflated, subsolid, with a low posterior ridge, with moderately full beaks, which are sculptured with numerous, delicate ridges looped up in the middle and open behind; surface rather smooth, scarcely shin- ing, greenish-straw-colored, sometimes faintly rayed, especially on the posterior slope ; left valve with two compressed, elevated pseudocardinals and two slightly curved, delicate laterals ; right valve with two pseudocardinals, the upper smaller and much compressed, and one lateral; beak cavities rather deep; muscle scars shallow; nacre ‘bluish-white, iridescent. Both male and female shells are somewhat produced at the posterior base, the female but slightly more than the male, and both are bluntly pointed behind midway up, or a little more than that, above the center of the shell. Length 67, height 40, diam. 25 mm. Tennessee River in northern Alabama. Type locality, Tennessee River, Tuscumbia, Ala. 94 LAMPSILIS Unio virescens Lea, Pr. Ac. N. Sci. Phila., II, 1858, p. 40; Jl. Ac. N. SetPhila., [V,;. 1860;py 441; ply iy, ike.) 166 5; °@ bs, VIII, 1860, p. 23, pl. Lv, fig. 166. Margaron (Unio) virescens Lea, Syn., 1870, p. 42. Lampsilis virescens SIMPSON, Syn., 1900, p. 544. This species seems to show affinities with members of the luteola and ventricosa groups. Some specimens are apparently close to L. anodontoides, but this species is much smaller, higher in proportion to its length, and there is, apparently, not so much difference between male and female shells. LAMPSILIS AUSTRALIS Simpson. Shell elongate ovate or long elliptical, subinflated, subsolid, with a low, rounded post-ridge; beaks not high, the sculpture not seen; suirface smooth, shining, with faint, irregular growth lines, greenish-yellow with feeble rays, a considerable space of the disk in the umbonal region is dark umber-color or blackish; left valve with two erect, somewhat compressed pseudocardinals, and two lamellar, slightly curved laterals; right valve with two pseudocardinals, the upper the smaller, and one lateral; beak cavities shallow; muscle scars rather shallow; nacre bluish-white, not thickened anteriorly. The type may be a young female. The two shells seen are rounded in front and slightly full behind the middle at the base, and pointed behind. Length (type) 52, height 27, diam. 15 mm. Length (co-tvpe) 72, height 38, diam. 24 mm. Type locality, Little Patsaliga Creek, southeastern Alabama. Lampsilis australis Simpson, Pr. Ac. N. Sci. Phila., 1900, p. 75, pl. u, fig. 2; Syn. 1900, p. 544. Only two specimens, the type and co-type, have been seen. The figured type is a young, fairly healthy shell, the other specimen is larger and has been injured probably by a ‘Trem- atod, as the teeth and cavity are brown or salmon-colored and rough. The posterior end of this shell is slightly injured and drawn down. Apparently a member of the anodontoides group, and most nearly related to L. recta. being nearly the LAMPSILIS 95 color of certain specimens of that species from Michigan, but it is shorter, less solid and inflated than that species, and has a large, dark blotch on the central and upper part of the shell. Lampsiis REcTA (Lamarck ). Shell large, elongated, dorsal and ventral lines nearly paral- lel, solid. inflated, rounded in front, pointed behind; with full but rather low beaks, whose sculpture consists of faint, delicate ridges, scarcely doubly looped; posterior ridge rather low, rounded ; ligament long; surface faintly and irregularly, con- centrically sculptured, varying from black to olive-green, gen- erally lighter colored in the umbonal region, the young and sometimes older shells often faintly rayed, left valve with two nearly equal, ragged, erect pseudocardinals and two long, slightly curved laterals; right valve with one pseudocardinal, a feeble, compressed one above it, and one lateral with a vestige of a second below it; muscle scars well impressed, smooth ; beak cavities shallow, with two or three deep dorsal scars; nacre purple or bluish-white, often whitish, with a purple flush at the beak cavities. The male shell is drawn out behind and ends in a blunt point about midway up from the base; the female shell has a long, rounded marsupial swelling and ends in a more blunt point two-thirds of the way up from the base. Length 150, height 65, diam. 45 mm. Entire Mississippi drainage; Alabama River drainage; Red River of the North; St. Lawrence system. Type locality, Lake Erie. Unio recta LAMARCK, An. sans Vert., VI, 1819, p. 74.—VAL- ENCIENNES, Rec. Obs. Zool., II, 1833, p. 234, pl. Liv, fig. I. Unio (Ligunia) recta Swainson, Treat. on Mal., 1840, pp. 267, 274, fig..55. Eurynia (Eurynia) recta ORtMANN, Am. Car Mus. VITil, 1912, p. 344, fig. 24. Unio rectus Conrap, Monog., III, 1836, p. 33, pl. xv,—Poriez and Micnaup, Gall. Moll., 1844, II, p. 149, pl. tv, figs. 3, 4. —Kuster, Conch. Cab. Unio, 1852, p. 35, pl. v1, fig. 15 pl. vu, fig. 1—CHENu, Man., 1859, II, p. 139, fig. 675.—REEVE, Conch. Icon., XVI, 186s, pl. xix, fig. 86.—Cat, Tr. Ac. Sci. St. Louis, VII, 1895, p. 43, pl. vil. g6 LAMPSILIS Margarita (Umo) rectus Lea, Syn., 1836, p. 34; 1838, p. 23. Margaron (Utio) rectus Lea, Syn., 1862, p. 35; 1870, p. 57. Lampsilis rectus SmirH, Bull. U. S. Fish Com., 1899, p. 290. pl. LXXVIII.—SIMPSON, Syn., Igo0, p. 544. Unio latissima RAFINESQUE, An. Gen. Sci. Phys. Brux., rt 13; V, 1620, p. 297, pl. Lx; fps) or, 75: ? Unio prelongus BARNES, Am. Jl. of Sci., VI, 1823, p. 261, pl. x11, fig. 11.—Hinpreru, Am. Jl. of Sci., XIV, 1828, p. 286, fig. 18. Mya prelonga Eaton, Zool. Text-Book, 1826, p. 220.—Woon, Ind. Test. (Hanley), 1856, p. 200, pl. 1, Supp., fig. 11. Eurynea prelonga Stimpson, Shells of N. Eng., 1851, p. 13. ? Unio arquatus Conran, JI. Ac. N. Sci. Phila., 1854, p. 297, pl. XXVi, fig: 8. Unio leprosus Mites, Rep. Geol. Sur. Mich., 1861, p. 240. Var. sagert (Conrad). Shell smaller than the type, with a more decided posterior ridge, below which it is somewhat compressed ; color chestnut, tawny, greenish or olive, often faintly rayed, rest periods gen- erally well marked; nacre bluish-white, rarely tinted purplish, often blotched ; marsupial swelling moderate. Length 95, height 42, diam. 28 mm. Type locality, Detroit River, Michigan. Also, Red River of the North. Unio sageri Conrap, Monog., VI, 1836, p. 53, pl. Xxx, fig. I. A very common, widely distributed form that should not be mistaken for any other. Conrad’s figure of Unio sageri is hardly characteristic, being too high in proportion to its length. The northern form is probably worthy of a varietal name. The specimens from the Alabama River drainage are smaller than those from the Mississippi Valley, but do not differ sufficiently to require a varietal name. DeCamp’s Unio anodontoides, reported from Michigan, is a tawny-colored variety of this species according to Walker, the Unio sageri of Conrad. LAMPSILIS 97. Group of Lampsilis nasuta. Shell elongated, thin, compressed, with a distinct posterior ridge, and drawn out to a long, pointed beak behind ; epider- dermis rather dull, olive-green, and feebly rayed; beaks low. sculptured with fine, close-set ridges, which are slightly looped in front and are parallel with the axis of the shell behind; hinge teeth delicate and compressed ; nacre bluish ; female shell not greatly produced in the post-basal region. Animal with the marsupium often occupying the greater part of the length of the outer gills posteriorly ; inner gills free or united to the abdominal sac. LAMPSILIS NASUTA (Say). Shell elongated, subcompressed, thin to subsolid, with a well- developed posterior ridge which is usually curved down in the middle; rounded in front; full at the base just behind the cen- ter, and drawn out to a long point behind midway up the height of the shell; beaks low, sculptured with fine, close ridges, which are looped in front and run parallel with the axis of the shell behind ; surface having irregular growth lines, and sometimes having a few nearly vertical ribs below the posterior ridges ; scarcely shining, dark olive to brownish or tawny, often faintly rayed, especially when young; left valve with a sort of double, compressed pseudocardinal and two delicate, nearly straight laterals; right valve with one compressed pseudocardinal, a faint one above it, and a lamellar lateral ; beak cavities shallow, with a row of dorsal scars visible; muscle scars shallow, the posterior indistinct; nacre bluish-white, lurid, flesh-tinted or purplish. Female shell with a long marsupial swelling just be- hind the center, not differing greatly from that of the male. Length 77, height 35, diam. 18 mm. St. Lawrence drainage; streams flowing into the Atlantic south to North Carolina. Type locality, Delaware and Schuylkill Rivers. Unio nasutus Say, Nich. Encyc., 1st ed., 1817, pl. iv, fig. I— Swainson, Zool. Ill., mst ser., I, 1821, pl. Lvit—ConraD, Monog., IV, 1836, p. 38, pl. xvutt, fig. 1, part—Goutp, Inv. 98 LAMPSILIS of Mass., 1841, p. 100, fig. 71—BinNey, Gould’s Inv., 1870, p. 169, fig. 473.—Der Kay, Zool. of N. Y., Pt. 5, 1843, p. 191. pl. xx, fig. 239—Kuster, Conch. Cab. Unio, 1861, p. 223, pl. Lxxv, fig. 4.—REEvE, Conch. Icon., XVI, 1865, pl. xx1, fig. 94—HartrMan and Micuener, Conch. Cest., 1874, p. 70, fig. 186. Margarita (Unio) nasutus Lea, Syn., 1836, p. 37; 1858, p. 24. Margaron (Umo) nasutus Lea, Syn., 1852, p. 37; 1870, p. 60. Lampsilis nasutus SIMPSON, Syn., 1900, p. 545. Mya nasuta Eaton, Zool. Text-Book, 1826, p. 218.—Woon, In- dex Test. (Hanley), 1856, p. 199, pl. 1, Supp., fig. 4. Eurynea nasuta Acassiz, Shells of New Eng., 1851, p. 13. Eurynia (Eurynia) nasuta OrtMANN, Am. Car Mus., VIII, IO12, p. 343- Unio rostrata VALENCIENNES, Rec. Obs. Zool., II, 1833, p. 233, pl. 11, fig. 3. Unio vaughanianus Sowrrsy, Conch. Icon., XVI, 1868, pl. LXI, fig. 308. No other living species seems to be very closely related to this, though Unio fisherianus is often mistaken for it. The lat- ter is a smaller, more compressed, smoother species, and its male and female shells are alike. There is a variety of Lamp- silis subrostrata found in the Wabash and in northern Ohio that sometimes resembles nasuta, but the posterior beak is not nearly so greatly drawn out. Group of Lampsilis subrostrata. Shell elliptical to elongate, distinctly pointed behind, the point well above the middle of the height, that of the female conspic- uously swollen at the posterior base and obliquely truncated behind ; epidermis varying from olive to brown, generally more or less rayed and slightly roughened; beaks not prominent, sculptured with fine, delicate, parallel bars, which are somewhat looped in front and generally descend obliquely behind; pseu- docardinals usually compressed; nacre bluish to purple. Ani- mal with inner gills often more or less free from the abdom- inal sac; posterior base of mantle of female generally toothed. LAMPSILIS 99 TAMPSIILIS SUBROSTRATA (Say). Shell elongated, irregularly elliptical, subsolid, somewhat in- flated, with moderately full beaks sculptured with numerous delicate ridges that are sharply drawn up in the middle; very slightly winged; rounded in front and rather sharply pointed behind ; growth lines irregular ; posterior ridge moderately de- veloped; surface dull, dirty greenish-yellow, generally having faint. wide, wavy rays on the hinder portion, often having con- centric bands of lighter and darker color; teeth compressed, two pseudocardinals in each valve, the upper in the right smaller, one lamellar lateral in the right valve and two in the left; muscle scars shallow ; beak cavities moderate; nacre blu- ish-white, scarcely thicker in front. The dorsal and ventral lines of the male shell are nearly parallel; it is more or less an- gled at the post-base and ends behind in a rather sharp point above the middle; the female shell is narrowed in front, with a very large, rounded marsupial swelling and in front of this the basal line is incurved. es: te Length (male) 70, height 35, diam. 23 mm. Length (female) 62, height 35, diam. 23 mm. ried Entire Mississippi drainage north to about latitude 41°. Eastern half of Texas. Type locality, Wabash River. Unio subrostratus Say, N. Harmony Diss., Jan. 15, 1831. Lampsilis subrostratus StMPSON, Syn., 1900, p. 546. Eurynia (Eurynia) subrostrata ORTMANN, Ann. Car. Mus., VITI, 1912, p. 344. Unio nashitllianus Lea, Tr. Am. Phil. Soc., V, 1834, p. 100, pl. xiv, fig. 43; Obs., I, 1834, p. 212, pl. xiv, fig. 43—Han- LEY, Biv. Shells, 1843, p. 193, pl. xxu, fig. 31.—KUSTER, Conch. Cab. Unio, 1861, p. 224, pl. Lxxv1, figs. 1, 2—Sow- ERBY, Conch. Icon., XVI, 1866, pl. xxx, fig. 158. Margarita (Unio} nashvillianus Lea, Syn., 1836, p. 26; 1838, p. 20. Margaron (Unio) nashiullianus Lea, Syn., 1852, p. 29. Margaron (Unio) nashvilliensis Lea, Syn., 1870, p. 45. 100 I.AMPSILIS Unio mississippiensis Conran, Jl. Ac. N. Sci. Phila., I, 1850, p. 277, pl. xxxvutl, fig. 11.—Kuster, Conch. Cab. Unio, 1861, p. 245, pl. LXxxu, fig. 3.—Rrrve, Conch. Icon., XVI, 1865, pl. xix, fig. 85. Margaron (Unio) mississip piensis LeA, Syn., 1852, p. 29; 1870, p. 60. Unio rutersvillensis Lea, Pr. Ac. N. Sci. Phila., III, 1859, p. 155; Jl. Ac. N. Sci. Phila., IV, 1860, p. 355, pl. Lx, fig. 181; Obs., VIII,. 1860, p. 38, pl. Lx, fig. 181. Margaron (Unio) rutersvillensis Lea, Syn., 1870, p. 43. Unio topekaensis Lea, Pr. Ac. N. Sci. Phila., XII, 1868. p. 144; Ji. Ac. N. Sci, Phila.,- VI, 1869, p.. 343, pl. xtax; fig. 126; Obs.; XIL} 1860, p. 935 ply) STAR) fies 126. Margaron (Unio) topekaensis LEA, Syn., 1870, p. 43. Unio cocoduensis Reeve, Conch. Icon., XVI, 1865, pl. xxv, fig. 117. Var. furva n. v. Shell generally more attenuated than the type and less in- flated, the marsupial swelling not so greatly developed. Epi- dermis varying from pale or smoky-brown to chestnut, not smooth or shining, occasionally with a few, faint posterior rays. In a few cases this form has much the same size and shape of typical specimens, but the color of the epidermis is always dark and nearly rayless. Type locality, North Indiana; Maumee River. An abundant species, especially in the southwest. Lea’s Unio nashvillianus appears to be a rather short, smooth, solid form. The variety furva comes from northeastern Indiana and prob- ably from the Maumee River drainage and seems to be almost distinct enough to be worthy of specific rank. Certain spec- imens of it approach 1. naswta, but it is rather more inflated than that species and the marsupial swelling is placed farther back ; besides, it is differently colored. I,AMPSILIS LIENOSA (Conrad). Shell long elliptical or slightly obovate, generally solid and inflated, with a faint posterior ridge ; beaks moderate, the sculp- CAMPSITAS Io! ture not seen; surface with irregular growth lines, often more or less sulcate, varying from dirty tawny to black, often faint- ly rayed behind; left valve with two granularly roughened pseudocardinals and two curved laterals; right valve with one pseudocardinal, a feeble lamellar tooth above, and one lateral with a vestige of another below it in old shells; laterals gran- ular; muscle scars small, well impressed; nacre white, salmon or flesh-colored, sometimes deep purple, slightly thicker in front. The male is often nearly rounded or sub-biangular be- hind, the posterior end at or above the middle of the height; the female shell is considerably swollen at the posterior base, and its posterior end is more elevated than that of the male. Length 70, height 43, diam. 30 mm. Lower Mississippi River drainage north to the lower Ohio and Wabash; east to southwest Georgia. Type locality, small streams in southern Alabama. Unio lenosus Conrap, Am. Jl. Sci., XXV, 1834, p. 339, pl. 1, fig. 4; Monog., VII, 1836, p. 60, pl. xxxtv, fig. 2—HANLEY, Biv. Shells, 1843, p. 194, pl. xxi, fig. 32—Kuster, Conch. Cab. Unio, 1852, p. 67, pl. xvi, fig. 3.—Sowerrsy, Conch. Icon., XVI, 1866, pl. xxxu1, fig. 166; 1868, pl. LXxv, fig. 388. Margarita (Unio) lenosus Lea, Syn., 1836, p. 26; 1838, p. 20. Margaron (Unio) lienosus Lea, Syn., 1852, p. 29; 1870, p. 45. Lampsilis lhenosus SIMPSON, Syn., 1900, p. 547. Unio saxeus Conrap, Monog., XII, 1840, p. 100, pl. 1x, fig. 1. Margaron (Unio) saxeus Lea, Syn., 1852, p 27; 1870, p. 42. Unio caliginosus Lea, Pr. Am. Phil. Soc., IV, 1845, p. 165; Tr. Am. Phil. Soc., X, 1848, p. 79, pl. vu, fig. 21 ; Obs., IV, 1848, p. 53, pl. vu, fig. 21—Kustrr, Conch. Cab. Unio, 1861, p. 180, pl. Lv1, fig. 7. Margaron (Unio) caliginosus. Lea, Syn., 1852, p. 29; 1870, p. 45. Unio fontanus Conrap, Am. Jl. Sci., II, 1866, p. 270, pl. xv, fig. 13. Var. unicostata (B. H. Wright). Shell smaller than typical lienosa and having in some cases a faint radial ridge running down the posterior slope. It is hard 102 LAMPSILIS to say just what this is, as it has the dull, dark color of enosa but something of the form of concestator and it may be a variety of the latter. Type locality, Spring Creek, Decatur Co., Ga. Unio unicostatus B. H. Wricut, Naut. XIII, 1899, p. 69. Lampstlis lienosus var. unicostatus SIMPSON, Syn., 1900, p. 547- LAMPSILIS CONCESTATOR (Lea). Shell elliptical or irregularly obovate, subinflated, subsolid, the beaks moderately full with a few doubly-looped ridges ; the growth lines irregular ; surface varying from yellowish or dirty tawny to blackish, generally having a few faint rays behind and somewhat shining; teeth granular; there are two subcom- pressed pseudocardinals in the left valve and one and a vestige of another in the right; two lamellar laterals in the left valve and one in the right; muscle scars shallow ; nacre whitish-flesh or straw-colored, salmon or deep purple, not much thickened in front. The male shell is nearly evenly elliptical or slightly obovate, the female shell is narrowed in front and greatly pro- duced at the post-basal region, it ends behind in an elevated and much sharper point than that of the male. Length (male) 60, height 38, diam. 25 mm. Length (female) 55, height 38, diam. 26 mm. North Carolina, in streams flowing into the sea, to Louis- iana, and possibly to Texas. Type locality, creeks, Columbus, Ga. Unio concestator Lea, Pr. Ac. N. Sci. Phila., [X, 1857, p. 31; Jl. Ac. N. Sci. Phila., IV, 1858, p. 66, pl. xm, fig. 48; Obs., VI, 1858, p. 66, pl. xu, fig. 48—Kuster, Conch. Cab. Unio, 1861, p. 178, pl. iv1, fig. 3—Reerve, Conch. Icon., XVI, 1865, pl. xxvi, fig. 128.—Simpson, Pr. U. S. Nat. Mus., XVI, 1892, p. 416, pl. Lvru, figs. 2-4. Margaron (Unio) concestator Lea, Syn., 1870, p. 45. Lampsilis concestator Simpson, Syn., 1900, Pp. 548. LAMPSILIS 103 Umio intercedens Lea, Pr. Ac. N. Sci. Phila., [X, 1357, p. 32): {ichc Nose. Phila, IV, 1858, ip: 77; pl. xv, fig. 57; Obs., MIS 1e58,-p- 77, pl xv, hie. 57. Margaron (Unio) intercedens Lea, Syn., 1870, p. 45. Umo fallax Lea, Pr. Ac. N. Sci. Phila., IX, 1857, p. 32; Jl. Ac. N. Sci. Phila., [V, 1858, p. 79, pl. xv, fig. 59; Obs., Vi1858 Pp. 79, pl. xv, fig. 59—Kusrer, Conch. Cab. Unio, 1861, p 206, pl. Lxvuir, fig. 7,—Sowrrsy, Conch. Icon., XVI, 1868, pl Lickxs Se. ATS: Margaron (Unio) fallax Liza, Syn., 1870, p. 45. Unio contiguus Lea, Proc. Ac. N. Sci. Phila., VI, 1861, peso2: Jl. Ac. N. Sci. Phila., V, 1862, p. 199, pl. xxvutt, fig. 268 ; Obs., IX, 1863, p. 21, pl. xxviui, fig. 268. Margaron (Unio) contiguus Lea, Syn., 1870, p. 45. Umo bi-celatus Rerve, Conch. Icon., XVI, 1865, p!. xxv1, fig. 130. Unio genuinus Lea, Pr. Ac. N. Sci. Phila., XX, 1868, p. 161; Ji. Ac. N. Sci. Phila., VI, 1868, p. 305, pl. xiv1, fig. 117; Obs., XII, 1869, p. 64, pl. xivt, fig. 117. Margaron (Unio) genuinus Lea, Syn., 1870, p. 45. Very close to L. lienosa, and there are specimens which I am unable to satisfactorily determine. As a rule lienosa is a larger , shell, is darker colored and not quite so shining, and it is solider. I,AMPSILIS PROPRIA (Lea). Shell rather small, long elliptical or subrhomboid, subsolid and subinflated, with rather low beaks, with a low, rounded posterior ridge; surface generally smooth, pale, smoky yellow- ish, sometimes with very faint rays behind; psetidocardinals subcompressed ; laterals short and lamellar; muscle scars shal- low ; nacre whitish, darker and often salmon or purplish in the center of the valves, but slightly thicker in front. Male shell subrhomboid, the somewhat rounded posterior point being near the base of the shell; female shell with but a moderate mar- supial swelling, the posterior point a little more than midway up from the base. : 104 LAMPSILIS Length 37, height 23, diam. 15 mm. Walker County, Georgia; Clinch River, Virginia. Type locality, Lafayette, Ga. Unio proprius Lwa, Pr. Ac. N. Sci. Phila., 1X, 1865, p. 89; Jl. Ac. N. Sci. Phila., VI, 1869, p. 256, pl. xxx1, fig. 70; Obs., XII, 1869, p. 16, Xxx1, fig. 70. Margaron (Unio) proprins Lea, Syn., 1870, p. 45. Lampsilis propriuns Simpson, Syn., 1900, p. 548. ? Unio striatus SowERBy, Conch. Icon., XVI, 1868, pl. Lx xvii, fig. 407. This may be only a variety of L. vanuxemensis, a most abundant and variable species. It is smaller than that shell and generally more tawny or yellowish. LAMPSILIS PUNICEA (Haldeman). “Shell ovate elliptical, regularly inflated, rather thick in tex- ture; short and obtuse anteriorly; slightly narrowed, and ob- tusely rounded posteriorly ; umbones eroded, and not elevated above the dorsal outline; umbonical slope undefined, posterior slope elevated; anterior teeth thick and direct, posterior ones short and straight; epidermis smooth, yellowish-brown, with well-defined dark green rays upon the posterior margin of the shell; inside light reddish-orange. Length 2.2, height 1.2, diam. 0.8 inch. Hab.: Holston River, Washington County, Virginia. Distinguished from U. tene- brosus by having more robust and direct teeth; and from U. muhlfeldianus, by being higher and more obtusely rounded in front, and less so posteriorly.” Unio puniceus HarpEMAN, J]. Ac. N. Sci. Phila., VIII, 1842, p.' 207. Margaron (Unio) puniceus LEA, Syn., 1870, p. 46. Lampsilis puniceus SIMPSON, Syn., 1900, p. 548. This species has never been figured, but from the description I take it to be a member of the subrostrata group, and it is very likely a synonym of some of the other species, a male L.. vanuremensis possibly. I give Haldeman’s description and remarks. LAMPSILIS 105 LAMPSILIS VANUXEMENSIS (Lea). Shell elliptical or irregularly obovate, rather solid, somewhat inflated, with a scarcely developed posterior ridge; beaks rath- er low, their sculpture a few ridges looped up in the middle: surface with irregular, concentric growth lines, which are often somewhat sulcate, dull colored, not shining, varying from dirty tawny through olive to nearly black; there are two rather stumpy pseudocardinals in the left valve and one and a vestige of another in the right; two curved laterals in the left valve and one in the right; muscle scars shallow, the posterior ones round; nacre varying from dirty purplish-white through sal- mon-tinted to dark purple, often darker in the cavity of the shell, slightly thicker in front, not bright. Male shell long elliptical, rather full at the posterior base and moderately sharp pointed behind about midway up the height of the shell. whe female shells have a large, prominent marsupial swelling at the extreme posterior base and the shell is truncated from this to the posterior point, which is situated two-thirds of the way up from the base. All the female shells I have seen are smaller than those of the males. Length (male) 58, height 36, diam. 23 mm. Length (female) 41, height 27, diam. 20 mm. Cumberland and Tennessee River systems; headwaters of the Coosa. Type locality, Cumberland River, Tenn. Unio vanuremensis Lea, Tr. Am. Phil. Soc., VI, 1838, p. 36, pl xi, me) 37 5 Obs, TL. 1838, p. 36, pl. x1; fie. 31. HAnrey, Biv. Shells, 1843, -p. 193, pl. xxu, fig. 56—Cuenu, II. Conch., 1858, pl. x1x, figs. 3, 3a, 3b—Kusrter, Conch. Cab. Unio, 1862, p. 272, pl. xct, fig. 6. Margarita (Unio) vanuremensis Lica, Syn., 1836, p. 26; 1838. p. 10. Margaron (Unio) vanuxemensis Lea, Syn., 1852, p. 20. Lampsilis vanuxemensis SIMPSON, Syn., 1900, p. 540. Eurynia (Micromya) vanuxemensis ORtMANN, Ann. Car. Mus., VILL, 1012, p. 342. Margaron (Unio) vanuxemt Lea, Syn., 1870, p. 46. Unio vanuxemu B. H. Wricut, Check List, 1888. 106 LAMPSILIS Unio nitens Lea, Pr. Am. Phil. Soc., I, 1840, p. 288; Tr. Am. Phil. Soc., VIII, 1843, p. 205, pl. x11, fig. 19; Obs., III, 1842, p. 43, pl. xu, fig. 19.—Kuster, Conch. Cab., 1856, p. 163, pl. XLVII, fig. 1—CHENU, Ill. Conch., 1858, pl. xxvii, figs. 5, 54, 5.—REEVE, Conch. Icon. XVI, 1865, pl. xxvi1l, fig. 144. Margaron (Unio) nitens Lea, Syn., 1852, p. 29; 1870, p. 45. Unio umbrosus Lea, Pr. Ac. N. Sci. Phila., IX, 1857, p. 32. Unio umbrans Lea, Pr. Ac. N. Sci. Phila., [X, 1857, p. 104; Jl. Ac. N. Sei. Philas V, 1888," ps72; pl sin ie 54 Onseey 1858, p. 72, pl. xiu, fig. 53—Sowersy, Conch. Icon., XVI, 1866, pl. xxxIv, fig. 179. Margaron (Unio) wmbrans Lea, Syn., 1870, p. 45. Unio tenebricus Lea, Pr. Ac. N. Sci. Phila., [X, 1857, p. 171; Jl: Ac. N. Sci. Phila., [V, 1858, p. 83, pl. xvuz, fig. 63; Obs., VI, 1858, p. 83, pl. xvu, fig. 63. Margaron (Unio) tenebricus Lea, Syn., 1870, p. 45. Unio pybasii Lua, Pr. Ac. N. Sci. Phila., II, 1858, p. 40; Jl. Ac. N:.. Sets. Phila... V;, 1862; 1p: -67,. plovi) fis: 216; Ops: ELT, 1862, p. 71, pl. vi, fig. 216. | Margaron (Unio) pybasu Lea, Syn., 1870, p. 45. Unio fabaceus Lea, Proc. Ac. N. Sci. Phila., V, 1861, p. 38; yiwe: Ne Sei) Phila, V1862;"p: Go; pl. xin, fig: 23a6p4abes VIII, 1862, p. 94, pl. x11, fig. 238. Margaron (Unio) fabaceus Lea, Syn., 1870, p. 46. Unio copei Lea, Pr. Ac. N. Sci. Phila., XII, 1868, p. 144; Jl. Ac. N. Sci. Phila., VI, 1869, p. 307, pl. xivu, fig. 120; Obs., XII, 1869, p. 67, pl. xvi, fig. 120. Margaron (Unio) copei Lea, Syn., 1870, p. 45. Unio dispansus Lea, Pr. Ac. N. Sci. Phila., I, 1871, p. 191; Jl. Ac. N. Sci. Phila., VIII, 1874, p. 19, pl. vi, fig. 16; Obs., XITL,.1874) p. 23) pk vi he. 16. A very abundant and variable species found in the Cumber- land, Tennessee and Alabama River systems. Unio tenebricus Lea seems to be a smaller, somewhat stunted form, but the transition to the type is so complete that I do not think it LAMPSILIS 107 worthy of even varietal rank. Unio copet is a little thinner and shorter than the ordinary manifestation of the species, and I am doubtful whether it is normal. LAMPSILIS OBSCURA (Lea). Shell long elliptical, subsolid, subinflated, rounded in front and pointed or slightly biangulate behind about midway up from the base; beaks rather low, with fine; double-looped sculpture; growth lines irregular, sulcated in front, the rest periods well marked; epidermis dirty greenish-yellow or yel- lowish-green, with very delicate, scarcely shining rays; there are two subcompressed pseudocardinals in each valve, the upper one in the right valve the smaller; one lateral in the right valve and two in the left; beak cavities shallow ; muscle scars not deep; nacre whitish at the edge, becoming purple in the cavity of old shells. All the shells ] have seen that are adult appear to be males. Length 51, height 28, diam. 19 mm. Tennessee and Cumberland River systems ; Lower Ohio sie its tributaries. Type locality, Nashville, enn. Unio obscurus Lea, Tr. Am. Phil Soc., VI, 1530, -p:°7, pl. 111, fig. 7; Obs., IT, 1838, p. 7, pl. 1, fig. 7 —Hantey, Biv. Shells, 1843, p. 194, pl. xxu1, fig. 58—Cuenu, Ill. Conch., 1858, pl. XVH, figs. 1, ta, 1b.—Kuster, Conch. Cab. Unio, 1861, p 2205 Ml VMI Me.< 3, Margarita (Unio) obscurus Lea, Syn., 1836, p. 26; 1838, p. 20. Margaron (Unio) obscurus Lea, Syn., 1852, p. 29; 1870, p. 45. Lampsilis obscurus SIMPSON, Syn., 1900, p. 549. Margarita (Unio) zeiglerianus Lea, Syn., 1836, p. 26; 1838, p. 20. Umo zeiglerianus Lua, Tr. Am. Phil. Soc., VI, 1838, p. 32, pl. x, fig. 27; Obs., II, 1838, p. 32, pl. x, fig. 27——Han ry, Biv. Shells, 1843, p. 193, pl. xxu, fig. 57—CueENu, IIl.:Conch., 1858, pl. xxiv, figs. 2, 2a, 2b.—Sowerrpy, Conch. Icon., XVI, 1866, pl. XxxvI, fig. 19. Margaron (Unio) zeiglerianus Lea, Syn., 1852, p. 20. Margaron (Unio) zieglerianus Lea, Syn., 1870, p. 45. 108 LAMPSILIS A puzzling form which is probably only a variety of vanux- emensis. lLea’s types of obscura and ziegleriana are probably the same, the latter being a younger shell. Lea has four young shells bearing the latter name, and I have seen two or three elsewhere, which may possibly not be this, but a related, un- described species. ‘The young shells I have seen are very del- icately rayed, the rays showing through at the posterior end, and are certainly different from the young of vanusemensis. I cannot be positive whether these young specimens develop into the mature ztegleriana or not as I have not seen material in all stages of growth. LAMPSILIS PRATTII (Lea). Shell small, elliptical or obovate, rather thin, somewhat in- flated, smooth and shining, yellowish-green or pale olive with feeble rays; beaks rather low, placed a little in front of the center of the shell, their sculpture not seen; there are two com- pressed pseudocardinals in each valve, the upper in the right valve small; two short, straight laterals in the left valve and one in the right; beak cavities shallow; muscle scars slightly impressed ; nacre bluish, dirty purplish in the center, iridescent behind, slightly thicker in front. ‘The male shell is nearly reg- ularly elliptical; the female has a well-developed post-basal swelling, and both are bluntly pointed behind. Length 33, height 22, diam. 14 mm. Chattahoochee River, Georgia. Type locality, Chattahoochee River, Roswell, Cobb Co., Ga. Unio prattii Lea, Pr. Ac. N. Sci. Phila., II, 1858, p. 166; Jl. Ac. N. Sci. Phila., IV, 1859, p. 206, pl. xxiv, figs. 88, 88a; Obs., VII, 1859, p. 24, pl. xxrv, fig. 88, 88a. Margaron (Unio) pratt Lea, Syn., 1870, p. 45. Lampsilis prattii Stmpson, Syn., 1900, p. 550. A rather attractive little species, which has a somewhat dif- ferent texture from any near allied forms. It is thinner and more shining than vanuxemensis, and the nacre is more iri- descent behind than it is in that species. LAMPSILIS 109 LAMPSILIS VAUGHANIANA (Lea). Shell subsolid, somewhat inflated, rounded and narrowed in front, pointed behind ; beaks not high, their sculpture not seen; © surface with strong, irregular growth lines, dirty yellowish- green or bottle-green with numerous feeble, wavy rays; there are two pseudocardinals in the right valve, the upper small and compressed, and one lateral; two rather stout, small, erect pseudocardinals in the left valve and two laterals; beak cavities not deep, but compressed, with a few dorsal scars. Anterior muscle scars separate, distinct ; posterior scars faint; nacre dirty white or straw-colored, iridescent behind, consider- ably thickened in front. I have only seen two shells of this species, both females. They are narrowed in front and pointed about two-thirds of the way up behind and have a very full, posterior, basal swelling. From this swelling to the posterior point the outline is straight or slightly emarginate. Length 50, height 30, diam. 17 mm. Type locality, Sawney’s Creek, near Camden, South Carolina, Margarita (Unio) vaughanianus Lea, Syn., 1836, p. 39; 1838, p25: Unio vaughanianus Lea, Tr. Am. Phil. Soc., VI, 1838, p. 5, pl. 1, fig. 5; Obs., II, 1838, p. 5, pl. m1, fig. 5 —HAN Ley, Biv. Shells, 1843, p. 208, pl. xxur, fig. 48.—CHENUu, IIl. Conch., 1858, pl. xx1, figs. Ifa, 11b. Margaron (Unio) vaughanianus Lea, Syn., 1852, p. 38; 1870, p. 6T. Lampsilis vaughanianus SIMPSON, Syn., 1900, p. 550. Close to L. ogeecheensis Conrad, and may be only a solid, dark, obscurely rayed variety of it. It is rather more inflated than that species, and narrower in front. LAMPSILIS OGEECHEENSIS (Conrad). Shell long elliptical or long obovate, rather thin, subinflated, with low beaks that have slightly doubly-looped sculpture ; sur- face with irregular growth lines, generally rather smooth and shining, pale greenish-yellow with bright, narrow or wide, IIO LAM PSILIS broken, green rays, often so disposed as to have concentric bands of the ground color; pseudocardinals compressed, two in each valve; two delicate laterals in the left valve and one in the right; beak cavities quite shallow; anterior scars not im- pressed: posterior scars very faint; nacre dirty pinkish or bluish with a purplish center, not thickened in front. The fe- male shell is shorter and higher than the male; it has a much- produced marsupial swelling and a blunt posterior point two- thirds of the way up from the base, the outline between these two points is straight or faintly emarginate: the male shell is pointed behind about midway up from the base. Length (male) 57, height 32, diam. 20 mm. Length (female) 53, height 36, diam. 23 mm. Neuse River, North Carolina; south to north Florida; west to the Etowah River, Georgia; Duck River, Tennessee. Type locality, Ogeechee River, Ga. Unio ogeecheensis Conrap, Ann. and Mag., N. Hist., 1V, 1849, p: 300; Ji. Ac. N. Sei Phila., I-1850, p. 275; pl. xxxViE Mes. 3, 4- Lampsilis ogeecheensis SIMPSON, Syn., 1900, p. 550. Unio prevostianus Lea, Tr. Am: Phil. Soc., X, 1852, p. 269,: pl. x1x, fig. 24; Obs., V, 1852, p. 25, pl. x1x, fig. 24.—Mus- GRAVE, Phot. Conch., 1863, pl. 11, fig. to. Margaron (Unio) prevostianus Lua, Syn., 1852, p. 29; 1870, Pp. 44. Umno proximus Lea, Pr. Am. Phil Soc., V, 1852, p. 252; Tr. Am. Phil. Soc.,:X,, 1852) p..2715 plox x ais. 27-Obs. . Ve reaes Pp. 275 pla fe. 273 Margaron (Unio) proximus LEA, Syn., 1852, p. 29; 1870, p.- 45. Unio tenerus Simpson, Pr. U. S. Nat. Mus., XV, 1892, p. 416, pl. nvr, figs. 5, 8. A species, which has something of the texture and coloring of members of the iris group, but the form of the shell is dis- tinctly that of the swbrostrata group. It seems to be distributed in the Atlantic, the Gulf and Mississippi drainage areas. LAMPSILIS III ILAMPSILIS CONSTRICTA (Conrad ). Shell rather small and short, subelliptical, subsolid, subcom- pressed; beaks not elevated, their sculpture evenly doubly- looped ridges ; surface nearly smooth or marked with irregular concentric growth lines; rather shining, yellowish-green, or bottle-green, feebly rayed; hinge somewhat solid; there are two pseudocardinals in the left valve and one and a faint sec- ond in the right; one straight lateral in the right valve and two in the left ; anterior muscle scars separate, somewhat impressed ; posterior scars faint; nacre bluish, sometimes purplish in the center, slightly thicker in front. The female shell is pointed behind a little more than midway up from the base, and be- tween this point and the small marsupial swelling the outline is generally a little emarginate. The male shell is often sub- rhomboid, the posterior point being generally less than midway up from the base. Length 38, height 26, diam. 15 mm. James River, Virginia ; south to South Carolina ; Floyd Coun ty, northwest Georgia; northern Alabama; Tennessee. Type locality, North River, Rockbridge Co., Va. Unio lienosus var. constrictus CONRAD, Monog., X, 1838, p. OT, pl xix; fig. 4. Unio constrictus Conran, Pr. Ac. N. Sci. Phila., VI, 1853, p. 247.—SoweErRpy, Conch. Icon., XVI, 1868, pl. Lxxxvil, fig. 404. Margaron (Unio) constrictus Lea, Syn., 1852, p. 29: 1870, p. 46. Lampsilis constrictus SIMPSON, Syn., 1900, p. 551. Unio genthiw Lea, Pr. Ac: N. Ser Phila., 1,°1857, p..85< Jl. Ac. Ne Sci, Phila: “1862, p. 57; pli, fig2204 > Obs., VIII, 1862, ‘NOt, plot ee 204). Margaron (Unio) genthii Lea, Syn., 1870, p. 41. There is quite a little difference in the degree of inflation and form of this shell; some specimens are subinflated and others are slightly elongated. It is distinguished from nearly allied forms by the shape of the post-basal swelling which as a tule does not project below the base line of the shell, and 112 LAMPSILIS by the emargination behind the swelling. The form found in the Atlantic drainage has generally received the name given by Conrad, while that found in the Tennessee system has been called by Lea’s name. A careful examination of a consider- able series of shells from both regions convinces me that they are identical. LAMPSILIS APICINA (Lea). Shell small, subsolid, smooth, elliptical, rather compressed, nearly equilateral, the posterior point less than half way up from the base, slightly and obliquely truncate above this point ; beaks rather full, regularly and beautifully sculptured with fine, doubly-looped ridges; ligament short; epidermis yellowish- brown, covered with small, nearly equidistant rays; pseudo- cardinals small, compressed, two in each valve; laterals deli- cate, nearly straight, two in the left valve and one in the right ; anterior cicatrices distinct, posterior faint; nacre bluish or purplish. Length 30, height 18, diam. 9 mm. Type locality, Othcalooga Creek, Gordon County, Georgia. Unio apicinas Lea, ProAc. N:"Sci., Phila.) 16,1667, p42, fl: Ac, N. Sci. Phila., TV, 1858,2p--76, pl. x fie, 56,7 Ons., VI, 1858, p:. 76, pl. xvE, fs: 56. Margaron (Unio) apicinus Lea, Syn., 1870, p. 44. Lampsilis apicinus SIMPSON, Syn., 1900, p. 551. I have only seen a few specimens of this shell; which is not represented in the [,ea collection, the type probably being lost. The specimens I have examined are most likely males, and I cannot be certain as to their relationship, but place the species here provisionally. LAMPSILIS OCCIDENTALIS (Conrad). Shell obovate or subrhomboidal, convex, thin or subsolid, rounded in front, bluntly pointed or subbiangulate behind; posterior ridge scarcely developed; beaks slightly elevated, their sculpture not seen, but probably having fine, doubly-loop- ed ridges; epidermis yellowish, yellowish-green or brownish, with numerous more or less distinct rays, mostly on the hinder LAMPSILIS 113 part of the shell, slightly shining; left valve with two pseudo- cardinals, the anterior larger, and two delicate, nearly straight laterals; right valve with two pseudocardinals, the lower larger, and one lateral; nacre bluish-white, tinted with purple in the center, or purplish throughout, scarcely thickened in front. Male shell somewhat rhomboid, the posterior point nearest to the base; female with a long, rather full marsupial swelling, slightly biangulate behind, the biangulation midway up from the base or a little higher. Length (male) 45, height 23 mm. Length (female) 40, height 23, diam. 15 mm. Length (female) 43, height 26, diam. 17 mm. Current and Little Red Rivers, Arkansas. Type locality, Current River, Ark. Umio occidentalis Conrap, Monog., VII, 1836, p. 64, pl. xxxXvI, fig. I. Margaron (Unio) occidentalis Lea, Syn., 1852, p. 33; 1870, p. 53: | Lampsilis occidentalis SIMPSON, Syn., 1900, p. 551. I have seen a half dozen female shells which I presume are the above species, but I have never seen a male shell. The largest specimen is dark and feebly rayed. It is probable that none of them are quite fully grown. These shells are from the Little Red River, Arkansas. They are something like female L,. concestator or unicostata, but are smaller and more delicate. LAMPSILIS NIGERRIMA (Lea). Shell obovate, rather thin to subsolid, subcompressed, with a scarcely developed posterior ridge ; rounded in front ; rounded or feebly bianulate behind ; beaks not inflated, sculptured with fine, slightly doubly-looped ridges; surface with irregular growth lines ; epidermis greenish-yellow to blackish, when fresh rather dull and cloth-like but becoming smoother and shining when rubbed, sometimes feebly raved behind; hinge line gen- erally evenly curved; left valve with two compressed pseudo- cardinals, the anterior higher, and two slightly curved, lamellar laterals ; right valve with two pseudocardinals, the lower much 113 LAMPSILIS the larger, and one lateral; beak cavities shallow, compressed ; muscle scars but slightly impressed ; nacre bluish-white, gener- ally dull, with a purplish or brownish center. Both male and female shells are somewhat obovate, the former round poste- riorly or slightly biangulate. The female shell is moderately produced at the posterior base, and nearly round behind or having a blunt posterior point two-thirds of the way up from the base. Length (male) 55, height 35, diam. 17 mm. Length (female) 55, height 37, diam. 18 mm. Eastern Texas; east to Enterprise, southeast Alabama; north possibly to southern Indiana. Type locality, Alexandria, La. Unio nigerrimus Lea, Tr. Am. Phil. Soc., X, 1852, p. 268, pl. XVII, fig. 23; Obs., V, 1852, p. 24, pl. xviml, fig. 23: Margaron (Unio) nigerrimus Liza, Syn., 1852, p. 31; 1870, p 49. Lampsilis nigerrimus SIMPSON, Syn., 1900, p. 551. Unio fuligo ReEve, Conh. Icon., XVI, 1856, pl. xxx, fig. 159- This species differs from L. lienosa in being thinner, more compressed, more rounded behind, and in being somewhat obo- vate. Group of Lampsilis iris. Shell rather small, elliptical, moderately solid in front, thin- ner behind; epidermis covered with dark green, broken rays, beak sculpture consisting of irregular ridges and corrugations that have a tendency to fall into two loops, which are some- times slightly nodulous below; nacre bluish, becoming beauti- fully iridescent posteriorly. Animal having the inner branchize free or united to the abdominal sac; mantle border often macu- lated and generally in the female having papilla below the mar- supium ; marsupium having a strong, deep sulcus parallel with or near to the base. LAMPSILIS 1R1S (Lea). Shell long elliptical or long ovate, inequilateral, subinflat- ed, with a low, rounded posterior ridge ; beaks low, compressed, sculptured with very irregular, broken ridges which show a LAMPSILIS EHS tendency to be doubly looped; surface covered with rather faint, irregular growth lines, pale yellowish or greenish-yellow, marked with numerous, wide or narrow, broken rays; left valve with two rather stumpy, small pseudocardinals and two small, lamellar laterals; right valve with one pseudocardinal, with usually a very faint, compressed one above it, and one lateral ; beak cavities shallow, with a few dorsal scars; muscle scars shallow, the posterior nearly circular; nacre bluish, somewhat iridescent behind, slightly thicker in front. The male shell is nearly evenly long ovate, often ending behind in a slight, narrow biangulation about midway up the shell; the female shell is slightly pointed behind midway up and has a moderate, rounded marsupial swelling, and is generally smaller than that of the male. Length (male) 65, height 34, diam. 20 mm. Length (female) 58, height 28, diam. 17 mm. St. Lawrence drainage; west to southern Michigan ; Ohio River system; Illinois and Wisconsin. ; Type locality, Ohio. Unio iris Lea, Tr. Am. Phil. Soc., III, 1830, p 439, pl. x1, fig. 18 ; Obs., I, 1834, p. 53, pl. x1, fig. 18.—Han_ey, Biv. Shells, 1843, p. 206, pl. xx1, fig. 37.—CueEnu, Ill. Conch., 1858, pl. vill, figs. 7, 7a, 7b.—RexEve, Conch. Icon., XVI, 186s). pl. XXIX, fig. 148. Margarita (Unio) iris La, Syn., 1836, p. 37; 1838, p. 25. Margaron (Unio) iris Lea, Syn., 1852, p. 38; 1870, p. 60. Lampsilis tris Baker, Moll. Chicago, Pt. 1, 1898, p. 105, pl. XI, fig. 1; pl. x1v, fig. 2—Simpson, Syn., 1900, p. 552. Eurynia (Micromya) iris OrtMANN, Ann. Car. Mus., VIII, I912, p. 341, fig. 23. Umo creperus Lea, Tr. Am. Phil. Soc., VI, 1838, p. 33, pl. x. fg. 28; Obs., II, 1838, p. 33, pl. x, fig. 28—Cuenv, III. Conch., 1858, pl. xxti1, figs. 5, 5a, 5b. Margarita (Unio) creperus Lea, Syn., 1836, p. 28; 1838, p. 20. Margaron (Unio) creperus Lea, Syn., 1852, p. 31; 1870, p. 48. Unio cresserus HANEY, Test. Moll., 1842, p. 106. 116 LAMPSILIS Unio novi-eboraci Lea, Tr. Am. Phil. Soc., VI, 1838, p. 104, pl. xxiv, fig. 114; Obs., II, 1838, p. 104, pl. xxiv, fig. 114.— De Kay; 'Zool-of No ¥.) Pt? 5; 1843) pres, fie. 240) — CHENU, Ill. Conch., 1858, pl. x1x, figs. 5, 5a, 5>—KusrTer, Conch. Cab. Unio, 1861, p. 221, pl. Lxxiv, fig. 4.—Sowerrsy, Conch. Icon., XVI, 1866, pl. xxxvut, fig. 206. Margarita (Unio) novi-eboraci Lea, Syn., 1838, p. 10. Margaron (Unio) now-eboraci Lea, Syn., 1852, p. 27; 1870, p. 60. Unio radiatus DeKay, Zool. of N. Y., Pt. 5, 1843, p. 189, pl. XVII, fig. 236. Unio subrostratus Kuster, Conch. Cab. Unio., 1861, p. 203, pl. LXVU, fig. 3—ReEEveE, Conch. Icon., XVI, 1864, pl. xvut, fig. 78. Some shells are scarcely rayed, having only a few faint, broken splashes of green. Lea places Unio opalinus Anthony (Am. J]. Conch, II, 1866, p. 145, pl. vu, fig. 2) in the synonymy of the above species. It is an oval, compressed, greenish-yellow shell according to the figure and description, and seems to have been injured ante- riorly. I cannot tell what it is. It is credited by Anthony to Michigan. LAMPSILIS FATUA (Lea). Shell rather elongated, sometimes long ovate, round before and usually behind, subinflated, subsolid, generally having a rather elevated, but rounded, posterior ridge, with low beaks, which have very irregular, broken, scarcely doubly-looped sculpture; surface covered with fine, irregular growth lines, yellowish-green, feebly or strongly rayed, rays scarcely broken, the posterior end of the shell usually darker than the anterior end; there are two small, sometimes irregular, subcompressed pseudocardinals in the left valve, and two delicate laterals; one pseudocardinal and a vestige of a second in the right valve and one lateral; beak cavities shallow; anterior scars scarcely impressed ; posterior scars rather faint ; nacre bluish- white, very much thickened in front, richly iridescent behind. LAMPSILIS 117 The male shells are sometimes feebly biangulate behind, but are more often rounded. I have only seen two female shells, one of which seems adult and both are much smaller than the shells of the males. They are rounded behind and have a feebly developed marsupial swelling. Length (male) 68, height 33, diam. 22 mm. Length (female) 45, height 23, diam. 16 mm. Tennessee system. Beaver River, Pennsylvania. (?) Type locality, Holston River, Tenn. Unio fatuus Lea, Pr. Am. Phil. Soc. I, 1840, p. 287; Tr. Am. Pils coe, V Ul 1842, 9.201, pl. xa. tie. 14; Obs.,. LLL, 1842; p. 39, pl. x1, fig. 14—CHENJ, IIl. Conch., 1858, pl. xx x1, figs. 4, 4a, 4b.—Kuster, Conch. Cab. Unio, 1862, p. 287, pl. xcv1, fig. 5. Margaron (Umo) fatuus Lea, Syn., 1852, p. 38; 1870, p. 61. Lampstlis fatuus SIMPSON, Syn., 1900, p. 553. Unio dactylus Lea, Pr. Am. Phil. Soc., I, 1840, p.. 287; Tr. Am. Phil. Sec. VL. 1842, p; 106, pl. 1x, fie.-7; Obs., IL, p. 24) pl. tx, fig. 7—Cuenu, Ill. Conch., 1858, pl. xxx, figs. 5, 5a, 5D. Margaron (Unio) dactylus Le, Syn., 1852, p. 36; 1870, p..57. I formerly doubted whether this species was distinct from L.. iris, but a recent examination of additional material con- vinces me that, though there are intermediate specimens, it is a valid species. It is generally longer in proportion than iris, it has a higher posterior ridge, it is less rayed and the rays are more entire. the posterior part of the shell is darker, the teeth are smaller and the front half of the shell is very much thicker. The thin hinder part of the nacre of fatwa is beauti- fully iridescent, with shades of blue and green predominating. LAMPSILIS PLANICOSTATA (Lea). Shell long elliptical or slightly rhomboid, subcompressed, scarcely subsolid, with low, compressed beaks that have irreg- ular, doubly-looped sculpture; surface with faint irregular, concentric growth lines, greenish-yellow, with broken, narrow or wide, green rays, which are often somewhat alternately ar- 118 LAMPSILIS ranged; left valve with two subcompressed pseudocardinals and two nearly straight, delicate laterals; right valve with one pseudocardinal and a faint one above it, with sometimes a slight tooth behind, and a single lateral; beak cavities shallow, compressed ; anterior muscle scars shallow ; posterior scars very faint ; nacre bluish-white, iridescent behind, slightly thicker in front. Male shell generally a little rhomboid, the posterior point being rarely biangulate and generally not greatly elevated above the base line, though sometimes it is midway up; female shell with a feebly developed, rounded marsupial swelling. Length 55, height 30, diam. 15 mm. Warren County, Kentucky; Clinch River, Tennessee ; Tus- cumbia, Alabama. Type locality, Tuscumbia, Ala. Unio planicostatus Lawa, Pr. Ac. N. Sci. Phila., IV, 1860, p. 92; Jl. Ac. N. Sci. Phila., IV, 1860, p. 354, pl. irx, fig. 179; Obs., VILI, 1860, p. 36, pl: Lax, ie. 176... Margaron (Unio) planicostatus Lea, Syn., 1870, p. 43. Lampsilis planicosiatus SIMPSON, Syn., 1900, p. 553- I am doubtful whether this is more than a mere variety of L. iris. It seems to be generally more compressed and wider behind; the males are more rhomboid as a rule, and the mar- supial swelling is less developed than in that species. LAMPSILIS NEBULOSA (Conrad). Shell irregularly long elliptical or subrhomboid, subcompress- ed to subinflated; beaks scarcely full, their sculpture consisting of a few, irregular, slightly doubly-looped ridges ; surface with irregular growth lines, greenish-yellow with narrow to wide, generally broken, rays, sometimes almost rayless; left valve with two somewhat compressed pseudocardinals and two near- ly straight laterals; right valve with two pseudocardinals, the upper the smaller, and one lateral ; beak cavities shallow ; pos- terior scars faint to distinct; nacre bluish-white, sometimes with pinkish or purple center, iridescent and slightly thinner behind. Male shell subrhomboid, the posterior point often — LAMPSILIS : 11g showing feeble traces of biangulation. Female shell somewhat rounded behind, with a faint marsupial swelling, generally smaller than the male. Length (male) 57, height 32, diam. 16 mm. Length (male) 52, height 31, diam. 18 mm. Length (female) 46, height 27, diam. 17 mm. Cumberland and Tennessee River systems; Green River, Kentucky ; Tombigbee and Alabama Rivers drainage; Colum- bus, Georgia; Wolfsville, North Carolina. Type locality, Black Warrior River, Ala. Unio nebulosus Conrap, New: F. W. Shells, 1834, p. 28, pl 11, fig. 7; p. 70.—CHENU, Btb. Conch., Ist ser., III, 1845, p. 16, ply, nets: Lampsilis nebulosus SIMPSON, Syn., T9Q00, p. 553. Margarita (Unto) cumberlandianus Lea, Syn., 1836, p. 27; 1838, p. 20. Margaron (Unio) cumberlandianus Lea, Syn., 1852, p. 30. Unio cumberlandicus Lea, Tr. Am. Phil. Soc., VI, 1838, p. 25, pl. vir, fig. 19; Obs., II, 1838, p. 25, pl. vu, fig. 19 —HANLEY, Biv. Shells, 1843, p. 195, pl. xxi, fig. 59.—CueENu, III. Conch., 1858, pl. xxiv, figs. I, Ia, 1b—Sowersy, Conch. licen, XV 11866, pls xxxvi, figy 197. Margaron (Unio) cumberlandicus Lea, Syn., 1870, p. 48. Unio notatus Lea, Tr. Am. Phil. Soc., VI, 1838, p. 28, pl. vii, fig. 22; Obs., IT, 1838, p. 28, pl. vu, fig. 22.—HANLEy, Biv. Shells, 1843, p. 193, pl. xxut, fig. 9 —CueEnu, Ill. Conch., 1858, pl. xx1, figs. 3, 3a, 3D. Margarita (Unio) notatus Lea, Syn., 1836, p. 26; 1838, p. 19. Margaron (Unio) notatus Lea, Syn., 1852, p. 29; 1870, p. 45. Unio glaber Lea, Tr. Am. Phil. Soc., VI, 1838, p. 34, pl. x, fig. 29; Obs., IT, 1838, p. 34, pl. x, fig. 29 —Han uy, Biv. Shells, 1843, p. 196, pl. xxi, fig. 2—Cuenu, Ill. Conch., 1858, pl. XXIV, figs. 3, 3a, 3b.—Sowersy, Conch. Icon., XVI, 1868, pl. LXxxv, fig. 452. Margarita (Unio) glaber Lua, Syn., 1836, p. 28; 1838, p. 20. Margaron (Unio) glaber Lea, Syn., 1852, p. 31; 1870, p. 48. 120 LAMPSILIS Unio radians Lea, Pr. Ac. N. Sci. Phila., IX, 1857, p. 32; Jl. Ac. N. Sei. Phila., TY; 1859; p: 201; pl) aay ae, 84) Obs, VII, 1859, p. 19, pl. xx111, fig. 84. Margaron (Unio) radians Lea, Syn., 1870, p. 46. Unto jonesti Lea, Pr. Ac. N. Sci. Phila., III, 1859, p. 171; Jl. Ac. N. Set: Philas IV, :1860;p. 330; pli a1v, fig. 164 33Ops., VIM, 1860, p; 21,.plenry; fig. 164: Margaron (Unio) jonesti Lea, Syn., 1870, p. 48. Unio discrepans Lea, Pr. Ac. N. Sci. Phila., [V, 1860, p. 92; Jl. Ac. N. Sei. Phila., TV, 1860;"p3340,;plh ty, fiesi05* Obs., VIII, 1860, p. 22, pl. Lv, fig. 165.—Sowerrsy, Conch. Icon., XVI: 1866, pl: xxxiv; fig: 176. Margaron (Unio) discrepans Lea, Syn., 1870, p. 48. Unio scitulus Lea, Pr. Ac. N. Sci. Phila., TV, 1860, p. 93; Jl. Ac. N. $c1.. Phila.,[LV,-1860; ‘p. 342, "pl. ty, fig.: 167;"Obs:; VIII, 1860, p. 24, pl. Lv, fig. 167. Margaron (Unio) scitulus Lea, Syn., 1870, p. 45. Unio lingueformis Lea, Pr. Ac. N. Sci. Phila., IV, 1860, p. 3053, Ji: Ac. N. Sei. Phila; TY , 1860, p..3245;. pl va, fiero; Obs., VIII, 1860, p. 27, pl. tv1, fig. 170. Margaron (Unio) lingueformis Lea, Syn., 1870, p. 48. Unio perpictus Lea, Pr. Ac. N. Sci. Phila., IV, 1860, p. 306; J]. Ac. N..Seiy Phila., 1V; 1860j.p>350, pl itv, ie.) 175 Obs, VIII, 1860, p. 32, pl. ivi, fig. 175. Margaron (Unio) perpictus Lea, Syn., 1870, p. 44. Unio sparus Lea, Pr. Ac. N. Sci. Phila., XX, 1868, p. 143; Jl. Ac. N. Sci. Phila., VI, 1868, p. 306, pl. xivu, fig. 119; Obs., XII, p. 66, pl. xivi, fig. 119. Margaron (Umo) sparus Lea, Syn., 1870, p. 45. Unio subrostratus Kuster, Conch. Cab. Unio, 1861, p. 203, pl: LXV he: 4: I have united a number of nominal species under this, which seems to be the oldest name. Conrad’s figure of U. nebulosus in the New Fresh Water Shells well represents a male specimen of Lea’s cumberlandicus and a number of other so-called spe- cies. Conrad states that his shell is thin, while a majority of the LAMPSILIS ; 121 specimens are subsolid, but it is often rather fragile. Unio dif- ficilis Lea, placed in the synonomy of nebulosa in the Synopsis, may be a form of L. planca Lea. LAMPSILIS MUHLFELDIANA (Lea). Shell irregularly long elliptical, solid in front, thin behind, scarcely subinflated, with low, compressed beaks sculptured beautifully with numerous, somewhat irregularly doubly-looped ridges ; surface with rather rude growth lines; dirty greenish- vellow with a few faint ravs; there is a slight elevation extend- ing from the beaks to a point on the base one-third of the dis- tance from the posterior end, and from this point to the some- what elevated posterior end the shell is somewhat truncated ; left valve with two roughened, equal pseudocardinals and two lamellar laterals; right valve with one pseudocardinal and one lateral; muscle scars distinct ; nacre whitish, shaded salmon in the cavity, iridescent behind. Length 60, height 34, diam. 20 mm. Type locality, Cumberland River, Tenn. Also, Watauga River near Johnson City, Tenn. Unio mihlfeldianus Lea, Tr. Am. Phil. Soc., VI, 1838, p. 41, pl. xu, fig. 36; Obs., II, 1838, p. 41, pl. xu, fig. 36.—HANLEY, Biv. pneliss 1843) p. 100, pil xxi, fie, 60:—Cuenu,. Ill. Conch., 1858, pl. xvit, figs. 5, 5a, 5b.—SowrErBy, Conch. Icon. XVI, 1666, pl. xxxviir, fe. 207. Margarita (Unio) miihifeldianus Lea, Syn., 1836, p. 27; 1838, De 20: Margaron (Unio) miihlfeldianus Lea, Syn., 1852, p. 30; 1870, p. 48. Lampsilis miihlfeldianus Simpson, Syn., 1900, p. 555. I have only seen a single specimen of this, the type, and I am doubtful whether it is a valid species, yet I cannot refer it to any other. Its coloration is something like that of adult specimens of 1. ziegleriana, but the shell is differently shaped. being somewhat truncated at the posterior base. 122 LAMPSITL,1S LAMPSILIS AMGNA (Lea). Shell long elliptical, the dorsal and ventral lines nearly par- allel, having the anterior and posterior ends rounded, subsolid, subinflated, without a dorsal ridge; beaks low, their sculpture not seen, growth lines irregular ; surface greenish-yellow, more or less wavy-rayed; left valve with two equal, rather small pseudocardinals and two laterals; right valve with one pseudo- cardinal, with a faint second one above it, and one lateral ; mus- cle scars well impressed ; nacre bluish-white, silvery, sometimes dark in the center, much thinner and iridescent behind. Fe- male shell apparently smaller than the male, and more evenly rounded behind, straight or very slightly incurved along the base in front of the moderately developed, rounded marsupial swelling. Length (male) 60, height 35, diam. 20 mm. Length (female) 50, height 27, diam. 16 mm. Type locality, Holston River, Tennessee. Unio amenus Lea, Pr. Am. Phil. Soc., I, 1840, p. 286; Tr. Am. Phil. Soc., VIII, 1842,.p..200, plex, fies 22; Obs, TIT, 2842, p. 38, pl. x, fig. 12—Han ey, Biv. Shells, 1856, p. 386, pl. XXIV, fig. 9.—CHENU, Ill. Conch., 1858, pl. xxx1u, figs. 5, 5a, 50.—Sowersy, Conch. Icon., XVI, 1868, pl. Lxx1x, fig. 416. Margaron (Unio) amenus Lea, Syn., 1852, p. 29; 1870, p. 45- Lampsilis amenus SIMPSON, Syn., 1900, p. 555. I am not certain that this is more than a variety of L. nebu- losa, but it is more oblong, the ends being nearly evenly round- ed, while nebulosa is pointed behind. J.AMPSILIS TENERA (Lea) Shell long elliptical or slightly obovate, subcompressed, sub- solid, feebly biangulate and showing a nearly evenly rounded outline behind; beaks low but utterly eroded away in all the specimens seen; surface with irregular growth lines, dirty greenish-yellow or tawny, with a few. faint rays, sometimes almost rayless; left valve with two smal! pseudocardinals and two delicate laterals; right valve with one pseudocardinal and LAMPSILIS 123 one lateral; muscle scars shallow; nacre dirty and livid. The male and female shells seem to differ but little, the latter appar- ently have a faint marsupial swelling. Length 60, height 35, diam. 17 mm. . Type locality, Big Pigeon River, Tenn. Also, French Broad River, Tenn.; near Bowling Green, Kentucky. Unio tener Lea, Pr..Am. Phil. Soc., I, 1840, p. 286; Tr. Am. Phil. Soc., VIII, 1840, p. 198, pl. x, fig. to; Obs., III, 1842, p. 36, pl. x, fig..10—CuHeEnu, Ill. Conch., 1858, pl. xxx1, figs. Tekh 0D Margaron (Unio) tener Lea, Syn., 1852, p. 28; 1870, p. 44. Lampsilis tener SIMPSON, Syn., 1900, p. 555. Unio regularis Lea, Pr. Am. Phil. Soc., II, 1841, p. 82; Tr. Hans Phals poc.,-V Il 1842, p. 243, pl. xxv, fig 59> Obs., III, 1842, p. 81, pl. xxv, fig. 59—CueENu, Ill. Conch., 1858, pl. XXXIII, figs. 3, 3a, 3b.—Sowersy, Conch. Icon., XVI, 1868, pl. Lxvint, fig. 351. Margaron (Unio) regularis Lra, Syn., 1852, p. 29; 1870, p. 45. Lea’s Unto tener is represented in his collection by only a single broken shell, which I have no hesitation in saying is iden- tical with his U. regularis, of which he has two very badly eroded specimens. LAMPSILIS SIMA (Lea). Shell oval or elliptical, not inflated, solid, with low, compress- ed. beaks, which are sculptured with irregular, somewhat doubly-looped ridges ; posterior ridge low and rounded ; surface rudely and irregularly concentrically striate in old specimens, smoother in young shells, yellowish-green, greenish-yellow or tawny, with numerous wavy rays, often shining in well-preserv- ed shells; left valve with two stumpy pseudocardinals and two short laterals ; right valve with one pseudocardinal and a feeble one above it, with one lateral; beak cavities shallow, showing a few dorsal pits; muscle scars well marked; pallial line well impressed in front; nacre pinkish or purple, sometimes bluish- white, with a darker center, thickened in front, iridescent be- hind. The male shell is somewhat oval, sometimes being 124 LAMPSILIS slightly produced at the anterior base, and occasionally straight on the basal line. All the female shells seen are smaller than the males; they are shaped much like those of the males but are a little fuller at the, post-base. Length (male) 52, height 30, diam. 19 mm. Length (female) 38, height 23, diam. 14 mm. Cumberland and Tennessee River systems; Othcalooga Creek, northwest Georgia. Type locality, Cumberland River, Tenn. Margarita (Unio) stimus Lea, Syn., 1836, p. 29; 1838, p. 21. Unto simus Lea, Tr. Am. Phil. Soc., VI, 1838, p. 26, pl. vii. fig. 20; Obs., II, 1838, p. 26, pl. vim, fig. 20.—Cuenu, II. Conch., 1858, pl. xx1, figs. 4, 4a, 4b—Kustrr, Conch., Cab. Unio, 1861, p. 248, pl. Lxxx11, fig. 4; p. 262, pl. Lxxxvitt, fe. Margaron (Unio) simus Lea, Syn., 1852, p. 31; 1870, p. 50. Lampsilis simus SIMPSON, Syn., 1900, p. 556. Unio notatus Conran, Pr. Ac. N. Sci. Phila., VI, 1853, p. 253.. Unio spatulatus Sowerby, Conch. Icon., XVI, 1868, pl. Lxv, fig. 328. ? Unio proximus Kuster, Conch. Cab. Unio, 1861, p. 248, pl. EXKXUED, dot 4. This species seems to combine characters of the ellipsiformts and the iris groups. Its solidity and form are characters of the former group, though the young shells are shaped like young nebulosa, while the beak sculpture and color pattern are those of the iris group. LAMPSILIS PLANCA (Lea). Shell irregularly obovate, subinflated, subsolid, with a well- developed, somewhat rounded posterior ridge; beaks rather full but not high, their sculpture not seen; surface rather smooth and shining, dirty greenish-yellow or dirty tawny, with a few wide or narrow, faint, often broken rays; left valve with- two small, stumpy pseudocardinals and two short laterals; right valve with one pseudocardinal, sometimes with a vestige of one above it, and one lateral; muscle scars well marked; beak cavities shallow ; nacre bluish-white, lurid in the center. ILAMPSILIS 125 30th male and female shells are wider behind, but the male shell is somewhat rhomboid, the somewhat biangulate posterior point being near the base of the shell. The posterior end of the female shell is usually faintly biangulate, but it is placed rather higher than in the male and the post-basal swelling is but feebly developed. ‘The female shell is higher than that of the male. Length (male) 42, height 27, diam. 16 mm. Length (female) 42, height 30, diam. 16 mm. Type locality, Coosa River at Wetumpka, Alabama. Unio plancus Lea, Pr. Ac. N. Sci. Phila., IV, 1860, p. 307; Jl. Ace Ny Sere Phila, V, 1602; p. Si, pl’x, fie. 2290; Obs:, VIL, 1862,.p.85, pl. x, fig. 220; Margaron (Unio) plancus Lea, Syn., 1870, p. 50. Lampsilis plancus SIMPSON, Syn., 1900, p. 5506. Umio ditficilis Lua, Pr. Ac. N. Sci. Phila., XIJ, 1868, p. 144; Jl. AGeNa pc Philas, V1, 1860) p. 311, ol KUPK he: 2A Obs., Poe Teo. p71) oi xix, fe 124) Margareon (Unio) difficilis Lea, Syn., 1870, p. 46. I am doubtful whether this is more than a rather short, some- what rhomboid variety of 1. nebulosa with a well-developed posterior ridge. The female shell, however, seems to differ in shape from that of nebulosa. Group of Lampsilis subangulata. Shell elliptical, inflated, subsolid, drawn to a point behind ; that of the female only slightly swollen just behind the central base ; bars of the beak sculpture somewhat coarse, feebly double looped; epidermis very smooth, shining, brightly rayed; teeth rather smooth, subcompressed ; nacre bluish or purplish. Ani- mal having the marsupium very large; ovisacs numerous; gills large, nearly semicircular. LAMPSILIS SUBANGULATA (Lea). Shell long elliptical or long ovate, rather solid, subinflated, with full, but not high, beaks, the sculpture not seen; posterior ridge well developed, slightly rounded; anterior end round; 126 LAMPSILIS base line curved, a little fuller behind the center of the shell; the posterior end drawn out into a rounded or slightly bian- gulate point about midway up from the base; surface, when in good condition, smooth and brilliant, tawny or pale greenish- yellow, distinctly marked with usually broad, green rays; left valve with two small, low, slightly compressed pseudocardinals and two short laterals; right valve with two pseudocardinals, the upper small and compressed, and one lateral; beak cavities not deep, but compressed ; muscle scars impressed, the anterior separate ; nacre bluish-white, lurid, pinkish-salmon or purplish, but slightly thickened in front. The male and female shells differ little, the latter is slightly more procuced behind the cen- ter of the base than the former. Length 57, height 33, diam. 20 mm. Appalachicola River system, Georgia and Florida. Type locality, Chattahoochee River, Columbus, Ga. Unio subangulatus Lea, Pr. Am. Phil. Soc., I, 1840, p. 287; Tr. Am: Phil. Soc:, VIII; 1842, pe20,, pl xml; fies 2357 Obs) TIT, 1842, p. 47, pl. x1, fig. 23—CueEnu, Ill. Conch., 1858, pl. XXIX, figs. 2, 2a, 2b.—Kustrer, Conch. Cab. Unio, 1862, p. 278, pl. xciv, fig. 2—Simpson, Pr. U. S. N. Mus., XVI, 1892, p 405; pleivin, fig. 1: Margaron (Unio) subangulatus Lea, Syn., 1852, p. 29; 1870 Pp. 45. Lampsilis subangulatus Simpson, Syn., 1900, p. 556. Unio fasciolus Conran, Pr. Ac. N. Sci. Phila., VI, 1853, p. 249. A brilliant and beautiful shell when in perfect condition. In fine specimens the rays are broad and distinct ; there are some- times intermediate narrow ones, and all are a rich green. Oc- casional specimens are nearly or quite rayless. LAMPSILIS KIRKLANDIANA (S. H. Wright). Shell’ elliptical or elliptic ovate, subsolid, subinflated, with full, rather high beaks, whose sculpture in the only specimen examined is eroded, with a high, but rounded, posterior ridge, which ends in a decided, drawn-out, rounded point about mid- way up the height of the shell; base line rounded, but slightly LAMPSILIS 127 fuller just behind the center; surface perfectly smooth except for rest lines, color greenish-yellow with beautiful broad, rich green rays throughout; between these broad rays there are narrower and fainter ones: epidermis polished and very bril- ant, wrinkled on the posterior slope ; ligament short and high ; left valve with three small, rather blurred, subcompressed pseudocardinals and two remote, short laterals, the hinge plate between the two sets of teeth narrowed and rounded; right valve with two pseudocardinals, the lower the larger, and a short, remote, high lateral. Beak cavities moderate; muscle scars shallow; nacre bluish-white, not brilliant, slightly irides- cent behind. The type is probably a male shell, though in this group there seems to be but little difference between the shells of the two sexes. Length 48, height 28, diam. 19 mm. Type locality, Ocklocknee River, Leon County, Florida. Unio kirklandianus S. H. Wricu, Naut., X, 1897, p. 136. Lampsilis kirklandianus Stimpson, Pr. Ac. N. Sci. Phila., 1900, p:-76, pl. 1, iss 7: Syms, 1900), p. 557. One of the loveliest Naiades in the world. The color pattern is exquisite, and the epidermis is more highly polished than in any Unione I know of. It closely resembles the brighter forms of subangulata, but it is much smoother and more brilliant, it has a higher posterior ridge. and feebler, more compressed pseudocardinals. Group of Lampsilis ellipsiformis. Shell elliptical, subinflated, pointed behind, that of the female but slightly swollen at the post-base ; behind this inflation there is a slight sinus; beak sculpture doubly looped, the hinder loop sometimes open behind ; epidermis dull, rayed with wavy lines, generally arranged in bands; nacre white. Animal with the marsupium colored below ; gills large, inner wholly united to or only free from the abdominal sac a short distance. 128 LAMPSILIS LLAMPSILIS ELLIPSIFORMIS (Conrad). Shell long elliptical or long ovate, subinflated, generally quite solid, sometimes very heavy, with a moderately rounded pos- terior ridge; beaks low, often flattened, lunule elongated, pass- ing back under the beaks; anterior end rounded; posterior end drawn out to a dull, rounded or biangulate point about midway up from the base; base line rounded, often a little fuller just behind the middle, and between this and the post-point the out- line is sometimes a little incurved ; surface with rude, irregular growth lines, greenish-yellow, or yellowish-green with numer- ous wavy, faint rays, often showing feeble, concentric bands or clouds of green. In front of the posterior ridge there are frequently deep, irregular, radiating grooves and sometimes finer and more regular radiating ones; epidermis often cloth- like, lusterless. There is little difference between the male and female shell, the latter being a trifle more produced behind the center of the base; pseudocardinals two in the left valve and one and a vestige of a second in the right, small, stumpy ; lat- erals short, rather heavy ; muscle scars deep; beak cavities very shallow, with a few pits; nacre bluish-white or flesh-colored, thicker in front, with a posterior, radial furrow. Length 72, height 42, diam. 28 mm. Iength 85, height 45, diam. 34 mm. Upper Mississippi Valley generally ; south to about latitude 38°; western New York; southern Michigan; southern Can- ada; Red River of the North. Type locality, Michigan. Unio ellipsiformis Coxrav, Monog., VIII, 1836, p. 60, pl. SRI e's Lampsilis ellipsiformis SIMPSON, Syn., 1900, p. 557. Unio spatulatus Lea, Pr. Am. Phil. Soc., IV, 1845, p. 164; Tr. Am. Phil. Soc., X, 1848, p. 80, pl. vit, fig. 22; Obs., IV, 1848, p. 54, pl. vin, fig. 22—Kusterr, Conch. Cab. Unio, 1861, p. 261, pl. Lxxxvil, fig. 7. Margaron (Unio) spatulatus Lea, Syn., 1852, p. 28; 1870, p. 43: Lampsilis spatulatus BAxrr, Moll, Chicago, Pt. I, 1898, p. 106, pl: X;, fig. 5 eam, fig. 2, LAMPSILIS 129 This species sometimes exceeds the above dimensions and is occasionally one of the most ponderous of North American Uniones. Other specimens, in unfavorable conditions, no doubt, do not exceed a length of 35 to 40 millimeters and are rather thin. LAMPSILIS PLEASII (Marsh). Shell small, long elliptical, subcompressed, scarcely subsolid, with low beaks, their sculpture not seen; growth lines irregu- lar; surface dirty tawny with numerous close, narrow, wavy rays, the whole dull colored and somewhat cloth-like ; posterior ridge low, rounded; left valve with two irregular, somewhat compressed pseudocardinals and two rather feeble, short lat- erals ; right valve with one pseudocardinal, a faint one above it, and one lateral; beak cavities shallow, with a few deep pits; anterior scars separate; nacre lurid greenish, bluish or brown- ish, slightly thickened in front. The shells of this species are somewhat drawn out behind and bluntly pointed about midway up from the base. The base line is rounded and a little full just behind the center ; that of the female differs but little from the male, it being slightly more produced in the region of the marsupium. Leneth 40, height 23, diam. 13 mm. Type locality, Little Red River, Arkansas. Also, Morrisville, Polk County, Missourt. Unio pleasiti Marsu, the Observer (a newspaper), II, May, 1891 ; Nautilus V, 1891, p. 2. Lampsilis pleasti SIMPSON, Syn., 1900, Pp. 557. All the specimens I have seen of this little species are in rath- er bad condition, being greatly eroded. | cannot be certain as to what the alliances are, but presume that it is related to L. ellipsiformis. It is smaller, more delicate and thin than that species, and the nacre is quite different. I.AMPSILIS ARKANSASENSIS (Lea). Shell ovate, subsolid, subinflated with a low, almost double posterior ridge, which ends in a slight biangulation behind about midway up from the base; above this posterior point 130 LAMPSILIS there is a slight oblique truncation and at the posterior end of the ligament there is an angle; the central base is full and from this point to the posterior end the outline is a little incurved ; beaks probably only moderately full, in the only specimen seen much eroded; surface irregularly concentrically striate, green- ish-tawny with very faint wavy rays behind; left valve with two nearly equal, small, biangular pseudocardinals and two short, club-shaped laterals; right valve with two pseudocardi- nals, the upper small and compressed, with one lateral and a vestige of another below it; beak cavities not deep, compress- ed, with several small scars; muscle scars well impressed ; nacre silvery with a faint reddish or brownish tint, iridescent behind, slightly thicker in front: pallial line well marked, cre- nate. Length 40, height 28, diam. 18 mm. Type locality, Hot Springs, Arkansas. Also, Saline River, near Benton, Arkansas. (Call.) Unio arkansasensis Lea, Pr. Ac. N. Sci. Phila., VI, 1862, p. 169; Ji Ae, N. Sct: Phila. -V,,. 1962) p.200spl. sxx, tis oa Obs; TS, A863: p- 2b plea, sone 7s: Lampsilis arkansasensis SIMPSON, Syn., 1900, Pp. 557. I have seen only one specimen that I feel sure is this shell, the type, and this is apparently a male shell. The whole um- bonal region is badly eroded, and it is not in the best condition generally, yet I know of nothing it can be referred to. It seems to be a member of the ellipsiformis group. Group of Lampsilis ozarkensis. Shell elliptical, rather solid, subcompressed, with low beaks slightly biangulate behind and showing the rest periods quite plainly. Pseudocardinals subcompressed ; laterals rather long, extended forward to near the pseudocardinals, the groove be- tween the two in the left valve extending forward behind the pseudocardinals and filled with epidermal matter ; nacre whit- ish-silvery ; male and female shells but slightly different. LAMPSILIS 131 ILAMPSILIS OZARKENSIS (Call). Shell elliptical, rather solid, not inflated, with a low, rounded posterior ridge, sometimes feebly doubly ridged; beaks low, their sculpture not seen; anterior end rounded; posterior end slightly produced, ending in a rounded or slightly biangulate point a little below the middle of the height of the shell; base rounded. a very little fuller behind the center; surface dirty yellowish-green, faintly wavy-rayed or rayless, showing numer- ous rest periods; epidermis somewhat cloth-like and dull; left valve with two stumpy or slightly compressed pseudocardinals, which are nearly equal in size, and two slightly curved laterals ; right valve with one pseudocardinal and a very small tubercle above it. with one lateral, which has a slight ridge along its lower base; beak cavities shallow, compressed; muscle scars well marked ; nacre bluish-white, silvery, with a reddish irides- cence behind. Male shell feebly biangulate behind, slightly rhomboid, rounded or scarcely biangulate at the post-basal ter- mination, in front of which there is a slight incurving of the base line. Female shell subbiangulate behind, the termination about midway up from the base ; marsupial swelling small, long and rounded, not close to the posterior end. Length 44, height 28, diam. 16 mm. Type locality, Current River and its tributaries, Jack’s Fork and Big Creek, Shannon County, Mo. Also, White River, Ark. Unio ozarkensis Catt, Pr. U. S. N. Mus., X, 1887, p. 498, pl. xxvit; Pr. Ac; Sci., St. Louis, Vil; 1895, p. 33;-pl. xvi, Lampsilis ozarkensis SIMPSON, Syn., 1900, p. 557. This species seems to stand somewhat by itself, though it has evident relations with the trabalis and ellipsiformis groups in its general form and color pattern. Group of Lampsilis trabalis. Shell solid, that of the male sinuate at post-base, and some- times produced posteriorly, female shell wider, but slightly sinuous: beak sculpture rather coarse, feebly doubly looped ; epidermis dark, with wavy capillary rays; hinge heavy ; nacre bluish-white or purple; animal unknown. 132 LAMPSILIS LAMPSILIS TRABALIS (Conrad). Shell solid, inflated, quite inequilateral, irregularly oval, with full, rather high beaks, which are turned forward and sculp- tured with a few coarse, doubly-looped ridges; lunule small, passing backward and filled with epidermal matter; posterior ridge somewhat full, rounded; surface with irregular growth lines, dirty olive-green, with numerous faint, wavy rays; left valve with two solid, triangular pseudocardinals and two long, straight, club-shaped laterals, the groove between them extend- ing to the epidermal matter of the hinge; right valve with three pseudocardinals, the central one solid and triangular, the oth- ers small, and one lateral with a vestige of a second below it; beak cavities shallow, showing a few dorsal scars; muscle scars deep; nacre white or bluish-white with bluish or greenish iri- descence behind, much thicker in front. The male and female shells differ remarkably, the-former being narrowed about at the center and drawn out behind into a sort of beak. This elongation is obliquely truncated above behind and ends in a rounded point below, the base line being generally a little in- curved; the female shell 1s higher, more nearly evenly ovate, slightly truncate behind above, and has the base line rather evenly curved. Length (male) 50, height 27, diam. 19 mm. Length (female) 54, height 35, diam. 25 mm. Kentucky and streams of Tennessee ; Clinch River, Virginia. ‘l'vpe locality, not given. Unio trabalis Conrap, New F. W. Shells, May 3, 1834, p. 27, pl. mu, fig. 5; p. 72; Monog., XII, 1840, p. 110, pl. Lx, fig. 2, —CneENu, Bib. Conch., 1st ser., ITI, 1845, p. 15, pl. 1, fig. 3. Lampsilis trabalis Simpson, Syn., 1900, p. 558. Eurynia (Micromya) trabalis OrtMANN, Ann. Car. Mus., VIII, 1912, p. 340. Unio troostensis Lua, Tr. Am. Phil. Soc., V, 1834 (August or September), p. 71, pl. x, fig. 30; Obs., I, 1834, p. 183, pl. x, fig. 30—Hantery, Biv. Shells, 1843, p. 186, pl. xx1u, fig. 24.—Kuster, Conch. Cab. Unio, 1861, p. 193, pl. LXt, fig. 4. —Sowersy, Conch. Icon., XVI, 1868, pl. Lxxvut, fig. 406. LAMPSILIS 133 Margarita (Unio) troostensis Lea, Syn., 1836, p. 21; 1838, p. 18. Margaron (Unic) troostensis Lea, Syn., 1852, p. 25. Margaron (Unio) troostu Lea, Syn., 1870, p. 39. Unio troostu B. H. Wricut, Check List, 1888. Unio vanuxemensis SOWERBY, Conch. Icon., 1866, pl. xxx1x, fig. 2106. A remarkable species, in which the form of the male shell is like that of the female until it is about half grown, when for some reason it begins to be constricted just behind the middle base and becomes much produced behind when adult. LAMPSILIS PERPURPUREA (Lea). Shell elongate oval or subrhomboid, scarcely inflated, some- times subcompressed, rather solid, beaks in all the specimens seen so badly eroded that no characters could be made out, but probably not very full or high; surface with irregular growth lines, dark brownish or blackish, darker behind, with feeble, narrow, wavy rays, which show plainly by transmitted light; left valve with two triangular pseudocardinals and two short, straight laterals; left valve with three pseudocardinals, the central one strong, the others faint, and one lateral with some- times a furrow on its lower face; beak cavities shallow, show- ing two or three deep pits; muscle scars impressed ; nacre deep purple, iridescent behind. The male and female shells differ considerably, but not so much as in L. trabalis. The male shell is somewhat drawn out behind and is straight or slightly incurved on the base; the female shell is irregularly long ovate, faintly incurved behind the feeble marsupial swelling. Length (male) 52, height 27, diam. 16 mm. Length (female) 55, height 31, diam. 18 mm. Tennessee River drainage, extending into Virginia in the Clinch. Type locality, Tennessee. Unio perpurpureus Lea, Pr. Ac. N. Sci. Phila., V, 1861, p. 41; So Ace N. Sen Phita., Vi, 1866,- ps-46, pl. xv1, fig. 44; Obs., XI, 1867, p. 50, pl. xvi, fig. 44. 134 LAMPSILIS Margaron (Unio) perpurpureus Lea, Syn., 1870, p. 48. Lampsilis perpurpureus SIMPSON, Syn., 1900, p. 558. Unio troostensis SoweRBy, Conch. Icon., XVI, 1868, pl. LXx1x, fig. 415. Very closely related to L. trabalis, and is sometimes a little difficult to determine badly eroded shells. L. perpurpurea seems to be thinner, more compressed, and less exaggerated in its peculiar characters than trabalis. Group of Lampsilis modioliformis. Shell elliptical, thin, quite evenly rounded before and behind, somewhat inflated ; beak sculpture consisting of a few parallel bars, looped in front, and generally open; epidermis with beau- tiful, rather broad, generally unbroken, sometimes slightly wavy rays; nacre brilliantly iridescent posteriorly ; teeth compressed. The female shell is greatly expanded posteriorly, the outline sometimes being almost arcuate on the middle base, and sweep- ing around in a regular curve to the ligament. Animal with mantle border often spotted, and in the female furnished with fine, well-developed papillae on the post-ventral region ; branch- ial opening large, with many strong papilla; marsupium pro- jecting greatly below the rest of the gills. rounded below ; ovi- sacs large and distinct. LAMPSILIS MODIOLIFORMIS (Lea). Shell long elliptical or long obovate, thin, somewhat inflated, with full, but not high, beaks, which are sculptured with num- erous rather fine, doubly-looped ridges, the hinder loop some- what angular below; surface rather smooth and shining, olive or yellowish-green, faintly rayed or almost rayless; left valve with two greatly compressed pseudocardinals, the anterior tri- angular and much the higher, and two very delicate laterals ; right valve with one pseudocardinal and sometimes a faint one above it, with one lateral; beak cavities shallow; muscle scars scarcely impressed, the anterior separate; nacre bluish- white, often tinted with purple, iridescent behind. Male shell long elliptical, sometimes slightly wider and bluntly pointed or LAMPSITAS E35 feebly biangulate posteriorly about midway up; female shell much narrower in front, considerably expanded behind where it is widely rounded. Length (male) 62, height 32, diam. 25 mm. Length (female) 70, height 37, diam. 25 mm. Santee Canal, South Carolina, south to north Florida; prob- ably west to Mississippi. Type locality, Santee Canal, S. C. Unio modioliformis Lea, Tr. Am. Phil. Soc., V, 1834, p. 97; pl. x11, fig. 40; Obs., I, 1834, p. 209, pl. x11, fig. 40.—HAan- LEY, Biv. Shells, 1843, p. 209, pl. xxi, fig. 37—-CHENU, Man., 1859, II, p. 139, fig. 678.—-Simrson, Pr. U.S. N. Mus., XV, 1892, p. 414, pl. Lv1, figs. 2, 3, 6. Margarita (Unio) modiolifornus Lea, Syn., 1836, p. 39; 1838, p. 25. Margaron (Unio) modioliformis Lua, Syn., 1852, p. 39; 1870, Dp. 44. Lampsilis modioliformis SIMPSON, Syn., 1900, p. 559. Unio tenerus RAVENEL, Cat., 1834, p. 58. Margarita (Unio) tenerus Laza, Syn., 1836, p. 39; 1838, p. 25. Margaron (Unio) tenerus Laza, Syn., 1852, p. 39; 1870, p. 44. Unio delumbis Kuster, Conch. Cab., 1861, p. 207, pl. LXIx, fig. I. Doubtfully distinct from L. vibex, though it is generally thinner, more inflated, less rayed, and the female shell is broad- er behind. Some of the young shells can scarcely be separated from the young of 1. vibex, and I have seen occasional old specimens that were very hard to place. All the valid speci- mens I have seen are from the Santee Canal, South Carolina. LAMPSILIS GRACILIOR (Lea). Shell elliptical or obovate, thin, scarcely subinflated ; beaks not full or high, their sculpture not seen ; posterior ridge almost wanting; surface with somewhat irregular growth lines, but rather smooth and shining, often showing the rest periods quite plainly, olive-brown, or olive-green, feebly rayed or nearly rayless; left valve with two compressed pseudocardinals, the 136 LAMPSILIS front one higher and larger, and two almost straight, delicate laterals; right valve with a single pseudocardinal and a vestige of one above it, with one lateral; beak cavities not deep; an- terior scars shallow, posterior scars scarcely visible; nacre blu- ish-white, often brownish or purplish in the center, iridescent behind. The male shell is very slightly rhomboid, sometimes feebly biangulate posteriorly, but generally rounded ; the female is scarcely produced at the post-basal region and is round behind. Length (male) 50, height 28, diam. 16 mm. Length (female) 48, height 29, diam. 15 mm. Type locality, Buckhead Creek and Tobesaufke Creek, Ma- con, Ga. Unio gracihor Lea, Pr. Ac. N. Sei. Phil., VIII, 1856, p. 262. Unio gracillior Lea, Jl. Ac. N. Sci. Phila., [V, 1858, p. 56, pl. vill, fig. 38; Obs., VI, 1858, p. 56, pl. vitt, fig. 38. Margaron (Unio) gracilior Lea, Syn., 1870, p. 45. Lampsilis gracilior Simpson, Syn., 1900, p. 559. Umio obfuscus Lea, Pr. Ac. N. Sci. Phila., IX, 1857, p. 172; Jl. Ac. N. Sci. Phila., IV, 1859, p. 197, pl. xxu, fig. 80; Obs., VII, 1859, p. 15, pl. xx, fig. 80. Margaron (Unio) obfuscus Lea, Syn., 1870, p. 45. Close to L. vibex, but generally thinner, smaller, less rayed and more delicate. LAMPSILIS VIBEX (Conrad). Shell varying from thin to subsolid, and from subcompressed to considerably inflated, long elliptical or long obovate ; beaks scarcely inflated or elevated, sculptured with a few doubly- looped ridges; growth lines irregular, often slightly sulcate ; surface smooth and shining, tawny or greenish-yellow, usually having wide, wavy rays, which may cover the entire shell or only the posterior part of it, occasionally nearly rayless; left valve with two somewhat compressed pseudocardinals, the anterior the higher and longer, and two delfcate, rather short laterals; right valve with one pseudocardinal and a vestigial LAMPSILIS 137 one above it, with one lateral; beak cavities not deep; muscle scars shallow; nacre bluish-white, slightly iridescent behind. Male shell sometimes sub-rhomboid, occasionally bluntly point- ed behind about midway up from the base, often nearly evenly rounded posteriorly ; female shell very slightly inflated at the post-basal part and evenly rounded behind. Length (male) 82, height 45, diam. 32 mm. Length (female) 74, height 43, diam. 27 mm. Ogeechee River, Georgia, west to Jackson, Mississippi. ‘Type locality, Black Warrior River, south of Blount Springs, Ala. Unio vibex Conrap, New F. W. Shells, 1834, p. 31, pl. Iv, fig. 3; p. 72——CHENU, Bib. Conch., Ist ser., III, 1845, p. 17, pl. 111, fig. 6. Marganta (Unto) vbexr Lea, Syn., 1836, p. 27; 1838, p. 20. Margaron (Unio) wbexr Lea, Syn., 1852, p. 30; 1870, p. 48. Lampsilis vibex SIMPSON, Syn., 1900, p. 559. Eurynia (Micromya) vibex Ortmann, Ann. Car. Mus., VIII, ° IQ12, p. 340. Unio exiguus Lea, Pr. Am. Phil. Soc., I, 1840, p. 287.—Tr. fem. Phils Soe, Wit; -1842, p:. 19x, pk vit; fig: 1; Obs:, ITI, 1842, p. 29, pl. vi, fig. 1—CHENU, II]. Conch., 1858, pl. xxx, figs. 1, Ia, 1b.—SoweERBy, Conch. Icon., XVI, 1866, pl. XXXVIII, fig. 208. Margaron (Unio) exiguus Lea, Syn., 1852, p. 27; 1870, p. 43. Unio stagnalis Conran, Ann. and Mag. N. Hist., [V, 1849, p. goa; sls Ac; Ne: Sct; Phila. I,,.1850; p. 275, pl. xxxvu, fig. .2. Margaron (Unio) stagnalis Lea, Syn., 1852, p. 27; 1870, p. 42. Unto rutilans Lea, Pr. Ac. N. Sci. Phila., VIII, 1856, p. 262; Hee. Noein inlay, LY, 1858, p. 50;.pl. 1x, fis. 41; Obs., VI, 1858, p. 59, pl. 1x, fig. 41—KustEr, Conch. Cab. Unio, TOO, fe 250. pill Tx x VIT, ties, 2. Margaron (Unio) rutilans Lea, Syn., 1870, p. 45. Unio subelipsis Lua, Pr. Ac. N. Sci. Phila., VIIJ, 1856, p. 262; TionGen: screiiia hy. Toso. po2rpl. x, figs 44; Obs., VI, 1858, p. 62, pl. x, fig. 44. Margaron (Unio) subellipsis Lea, Syn., 1870, p. 45. 138 LAMPSILIS Unio prevostianus SoweERBy, Conch. Icon., XVI, 1868, pl. LX, Hears: Unio subangulatus Sowerby, Conch, Icon., XVI, 1868, pl. -xv, fig. 327. Var. nigrina (Lea). Shell generally smaller than the typical form, more narrowed in front, thinner, darker colored and less shining. The nacre is coppery or purplish. Length 55, height 33, diam. 18 mm. Florida, south to the Hillsborough River. Type locality, West Florida. Unio nigrinus Lea, Tr. Am. Phil. Soc., X, 1852, p. 284, pl. XXIV, fig. 44; Obs., V, 1852, p. 40, pl. xxiv, fig. 44. Margaron (Unio) nigrinus Lea, Syn., 1852, p. 39; 1870, p. 62. Lamfsilis vibex var. nigrinus SIMPSON, Syn., 1900, p. 560. Unio floridensis 5. H. Wricut, Conch. Exchange, II, 1888, p. 105. Unio averillu B. H. Wricut, Pr. Ac. N. Sci. Phila., XXIII, 1888, p. 115, pl. 11, fig. 2. An abundant, rather widely distributed form and quite vari- able. Lea's subellipsis is generally a little solider and more narrowly rayed than the average forms, but it hardly seems to me to be worthy of a varietal name. I have seen shells from the Cahawba River, Alabama, which are, no doubt, genuine vibe-x. though they are more inflated and pointed behind than speci- mens found elsewhere, but I do not think they are specifically or even varietally different from exiguus, rutilans or subellip- sts. LAMPSILIS DISPAR (Lea). Shell long elliptical, scarcely subinflated, subsolid, with a low, rounded posterior ridge; beaks rather low, their sculpture not seen; surface with fine growth striz, often showing faint, radiating rows of short wrinkles; tawny, pale yellowish or yellowish-green with rather feeble rays on the front part of the shell, but more developed on the hinder part, where they are LAMPSILIS 139 sometimes blended together ; left valve with two subcompressed pseudocardinals, the anterior much the higher; right valve with two pseudocardinals, the upper very small and lamellar and one lateral; beak cavities shallow, with two or three dorsal pits; nacre whitish, bluish-white, brownish or lurid purplish, scarcely thicker in front. Male shell evenly elliptical or slight- ly rhomboid, rounded or faintly biangulate behind ; female shel! rounded behind with only a very small marsupial inflation. Length 55, height 32, diam. 20 mm. Southwest Georgia. Type locality, Columbus, Ga. Unio dispar Lea, Pr. Ac. N. Sci. Phila., 1V, 1860, p. 305; Jl. Ac. Ne Sci. Philaz LV, 1600): pi 327, ply 11; fig. 11537 Obs:, VIM 1860;.p- O,spl. 1,15. figs 153: Margaron (Unio) dispar Liza, Syn., 1870, p. 45. Lampsilis dispar S1MPSON, Syn., 1900, p. 561. This species is close to L. vibex, but is generally smaller and a little solider, the marsupial swelling is less developed, and it is darker posteriorly than that species. Group of Lampsilis amygdalum. Shell rather small, obovate, inflated, epidermis varying from smooth and shining to somewhat cloth-like, ashy-green or black- ish, but always showing green tints when seen through trans- mitted light, indistinctly rayed; beaks rather high, sculptured with fine, parallel bars, arranged in a double loop, that in front being large and rounded, that behind small and rather pointed below ; hinge teeth compressed; nacre iridescent behind. The greatest height of the shell is just behind the center ; its great- est diameter is just in front of it, or at a point just behind the beaks ; the posterior end is often pointed and somewhat raised. Animal having the marsupium large, reaching far below the inner gills, and having a black border; inner gills united to the abdominal sac throughout ; anal opening smooth or only slightly crenulate, 140 LAMPSILIS LAMPSILIS AMYGDALUM (Lea). Shell elliptical or obovate, somewhat inflated, with full, rath- er high beaks, which are sculptured with fine, doubly-looped bars; color varying from dirty greenish-white to almost black, with numerous rather faint rays or rayless; epidermis smooth and shining to rather rough, dull and cloth-like ; left valve with two elongated, compressed pseudocardinals and two delicate laterals; right valve with one pseudocardinal and a single lat- eral ; beak cavities not deep; muscle scars shallow ; nacre bluish- white, creamy or buff-colored, soft and brilliant, richly irides- cent behind. The shells are very variable in form and degree of solidity ; the males are generally elliptical with a low, round- ed posterior ridge, with a slight dorsal wing and a more or less blunt posterior point about midway up from the base. The fe- male shell is usually narrowed and rounded in front, and is al- most always darker and rougher than that of the male. Length 47, height 29, diam. 18 mm. Florida. Type locality, Lake George, Fla. Unio amygdalum Lea. Desc. of twelve sp. Uniones, Aug. 19, 1843; Tr. Am. Phil. Soc., IX, 1846, p. 275, pl. xxx1x, fig. 1; Obs., IV, 1848, p. 33, pl. xxx1x, fig. 1—Simpson, Pr. U. S. Nat. Mus., XV, 1892, p. 426, pl. Lxvut, fig. 3. Margaron (Unio) amygdalum La, Syn., 1852, p. 39; 1870, Pp: (62. Lampsilis amygdalum Simpson, Syn., 1900, p. 561. Unio lepidus Gout, Pr. Bost. Soc. N. Hist., VI, 1856, p. 15: Otia Conch., 1862, p. 222.—Simpson, Pr. U. S. Nat. Mus., SEV, 1892p: 426; pl ixeviniy fig ar pple Ree, te Margaron (Unio) lepidus Lea, Syn., 1870, p. 39. This is an excessively puzzling form. Generally, but not always, the female shell is darker and rougher than that of the male. The form usually known as lepidits, is ordinarily larger and a little more elongated than typical amygdalum and it is larger and solider, though I have specimens before me that are LAMPSILIS I4I brightly rayed and polished. It seems to so completely blend with amygdalum that I cannot make any satisfactory separa- tion. It might however bear Gould’s name varietally. LAMPSILIS SUDA (Lea). Shell elliptical or slightly obovate, subinflated, scarcely sub- solid, beaks nearly central, rather full but not high, their sculp- ture consisting of a few doubly-looped ridges, the hinder loops somewhat angular below ; posterior ridge rather well developed, rounded ; surface with irregular, concentric growth lines, shin- ing, tawny or pale brownish with regular, somewhat broken rays; left valve with two compressed peudocardinals, the an- terior much higher and triangular, and two delicate, nearly straight laterals; there are two pseudocardinals in the right valve, the lower the larger, and one lateral ; beak cavities shal- low; nacre bluish-white, rather dull; muscle scars shallow. Male shell elliptical or very feebly subrhomboid, the posterior point midway up from the base or a little iess; base much rounded. Female shell wider behind than in front, with a blunt, rounded posterior point two-thirds of the way up from the base, and a small, rounded marsupial swelling situated near the posterior end. Length 42, height 27, diam. 16 mm. Type locality, Macon and Dry Creek, near Columbus, Geor- gia. Also, Abbeville, South Carolina. Unio concavus Lea, Tr. Am. Phil. Soc., X, 1852, p. 260, pl. KV, fig. 11; Obs., V, 1852, p. 16, pl. xv, fig. 11—SOWERBY, Conch. Icon., XVI, 1868, pl. xcu, fig. 504. Margaron (Unio) concavus Lea, Syn., 1852, p. 29; 1870, p. 46. Unio sudus Lea, Pr. Ac. N. Sci. Phila., IX, 1857, p. 170; Jl. Aciiesciotiilaa IT To50.p 194, pl xx, fie. 77 ;Obs., WLS tS50; psi2, pl. xx, hie. 77. Margaron (Unio) sudus Lea, Syn., 1870, p. 46. Lampsilis sudus Stmpson, Syn., 1900, p. 561. This seems to be a rare shell, and I have never seen more than half a dozen specimens of it. Of these a single young one is a female and I cannot be certain whether the species 142 LAMPSILIS should group here. It differs from amygdalum in its color, in having its greatest diameter well towards the posterior end, in having a dull colored nacre, and in being much more nearly equilateral. The name concavus applied by Lea was, I believe, used by Zelebor for what seems to be U. tumidus. LAMPSILIS VESICULARIS (Lea). Shell small, subinflated, scarcely subsolid, elliptical or obo- vate, with a very low posterior ridge; beaks apparently low, but so eroded in the specimens seen that nothing of their char- acter could be made out ; surface having irregular growth lines, brownish or dirty yellowish-green, with only the faintest indi- cations of rays, somewhat shining, darker behind; left valve with two low pseudocardinals, the front one rather elongated, the hinder triangular, and two straight laterals; right valve with one pseudocardinal, a vestige of one above it, and an- other behind it, with one lateral; beak cavities very shallow, with two or three small dorsal pits; muscle scars small, well impressed, the anterior ones separate; nacre whitish-silvery. brilliantly iridescent behind. The female shell has a rounded marsupial swelling. Length 32, height 19, diam. 12 mm. Type locality, Lake Okeechobee, Sumpter County, Florida. Also, Flint River, Georgia. Unio vesicularis Lea, Pr. Ac. N. Sci. Phila., II, 1872, p. 156; jh. Ac IN. Sci. Phila, Vill, -1874,:p:'37; pl. xu, fie, s40;/Obs., XIII, 1874, p. 41, pl. x11, fig. 34.—Simpson, Pr. U. S. N. Mus., XV, 1892, p. 425, pl. Lxvit, fig. 4. Lampsilis vesicularis StMpson, Syn., 1900, p. 562. Two shells bearing this name are in the Lea collection, one a pair of matched valves, which I think are a variety of lepidus, and these are from female shells. The other, the figured type, is smoother, more shining, much more silvery within, is rather elongated, lightly obovate, nearly evenly rounded at both ends and is probably a male shell. It seems nearest to L. singley- ana. It is very close to forms of amyvgdalum and I have seen LAMPSILIS 143: intermediates, which I could not satisfactorily place. The texture of typical forms is different from that of amygdalum, being decidedly waxy, and the nacre is rather more silvery. LAMPSILIS VILIOSA (B. H. Wright). Shell long obovate, subsolid, somewhat inflated, its greatest diameter just forward of the center, rounded before and be- hind ; posterior ridge almost wanting; beaks low but moder- ately wide, their sculpture not seen; epidermis dark olive-green to blackish, somewhat shining in the umbonal region, cloth-like around the edges of the shell, rayless or very feebly rayed; left valve with two ragged pseudocardinals, the anterior the higher, sometimes partly connected on their upper edges and having a faint pit between them, with two long, slender laterals ; right valve with one pseudocardinal and a vestige of one above it, with one lateral; beak cavities shallow ; muscle scars scarcely impressed; nacre bluish-white to lurid, somewhat iri- descent and scarcely thinner behind. Female shell with a slight, wide, rounded inflation at the pest-base. Length 42, height 23, diam. 17 mm. Suwanee and F'scambia Rivers, Florida. Type locality, Suwanee River, Suwanee County, Fla. Unio villosus B. H. Wricut, Naut., XII, 1898, p. 32. Lampsilis villosus Stmpson, Pr. Ac. N. Sci. Phila., 1900, p. Ze Die elieer hs Syl st OOO, Pp. 562: A species combining the characters of L. amygdalum and minor to some extent. The pseudocardinals have some resem- blance to those of the latter. It is more elongated than either. species. LAMPSILIS TROSSULUS (Lea). Shell elliptical, subinflated, rather solid, with full, slightly elevated, anterior beaks, which are sculptured. with distinctly doubly-looped ridges, the hinder loop angular below; with a moderately developed posterior ridge; surface with low, con- centric growth lines, smooth and shining, greenish-yellow with faint rays, being quite green behind and wrinkled on the pos- 144 LAMPSILIS terior slope; left valve with two ragged pseudocardinals, the anterior higher and subcompressed, posterior low and _ feebly developed, with two nearly straight laterals; right valve with one pseudocardinal and a faint one above it, with two laterals, the lower smaller but well developed; beak cavities very shal- low, with a few small scars; muscle scars small, somewhat im- pressed; nacre brilliant, silvery and iridescent, especially be- hind, and having a rather bluish tint. Length 35, height 21, diam. 15 mm. Type locality, Lake Monroe, Florida. Unio trossulus Lea, Desc. 12 sp. Uniones, 1843; Tr. Am. Phil. Soe., IX, 1846, p. 278, pl. xi, fig. 6; Obs., IV, 1848, p. 36, pl. xt, fig. 6—Simpson, Pr. U. S. Nat. Mus., XV, 1892, p. 427, pl. Lxvitt, fig. 3. Margaron (Unio) trossulus Lea, Syn., 1852, p. 25; 1870, p. 39. Lampsilis trossulus SiMPSON, Syn., 1900, p. 562. I have seen no shell but the type that I can refer with cer- tainty to this species. This specimen is probably a rather young male shell and resembles the bright male specimens of amygda- lum in some respects. But it is much solider, the hinge is heavier and straighter, and the beaks are more anterior. It seems strange if it is a valid species that the numerous collec- tions made in Lake Monroe should not contain other specimens. There are examples which seem to stand between this and amyedalum. LAMPSILIS PELLUCIDA (Lea). Shell very thin, obovate, rather compressed to slightly in- flated, smooth, inequilateral, the posterior ridge full and round- ed; beaks not high, with fine, somewhat doubly-looped ridges ; surface smoky brown, with numerous undulating, faint rays: pseudocardinals two in the left valve, the hinder smaller, and one in the right, with a vestige of a second above it, all com- pressed ; two laterals in each valve, the upper in the right valve very faint, all of them delicate and but feebly developed ; an- terior muscle scars distinct; posterior scars confluent; nacre bluish-white, iridescent. The figure of the type represents a LAMPSILIS . VBS female shell, which is rounded behind and has a small, mar- supial swelling placed well back. The writer found a dead shell at Columbus, Georgia, in the Chattahoochee River, which seems to be a male of this species. It is a little longer in pro- portion than the figure, and is bluntly pointed behind about midway up from the base. Length (male) 36, height 21, diam. 13 mm. Length (female) 33, height 20, diam. 12 mm. Flint and Chattahoochee Rivers, Georgia. Type locality, Chattahoochee River, Ga. Unio pellucidus I,a, Pr. Am. Phil. Soc., IV, 1845, p. 163; Tr. Am. Phil. Soc., X, 1845, p. 70, pl. 1, fig. 6; Obs., IV, 1848, p. 44, pl. 11, fig. 6. Margaron (Unio) pellucidus Lea, Syn., 1852, p. 39; 1870, p. 62. Lampsilis pellucidus Stimpson, Syn., 1900, p. 562. The type is not in L,ea’s collection, but belonged to Major Le Conte. It is a remarkably thin shell, of a peculiar, smoky- brown color, rather dark, with numerous darker, wavy, faint rays. In the shell found by the writer the nacre has been somewhat weathered and has turned dark, but in places where it is perfect it is brilliantly iridescent. LAMPSILIS MINOR (Lea). Shell small, subsolid to solid, obovate, intlated, its greatest diameter just behind the beaks, from which point to the pos- terior end it is wedge-shaped ; posterior ridge wanting ; beaks full, but not high, their sculpture not seen; epidermis black, thick, and cloth-like, rayless ; left valve with two rather ragged, solid pseudocardinals, the hinder the larger and higher ; they are often united by a ridge on their upper side, and have a pit between them, and two small laterals; right valve with one strong pseudocardinal and one lateral. There is sometimes an extra, small, anterior pseudocardinal in each valve; anterior scars deep; posterior scars well marked: nacre bluish-white, sometimes a little lurid in the center, brilliantly iridescent be- 146 | ILAMPSILIS hind, thicker in front. Both male and female shells are slightly obovate and rounded behind, the female has a considerably produced rounded, marsupial swelling near the posterior end. Length 30, height 17, diam. 13 mm. Florida and southwestern Georgia. Type localitv, Lake Monroe and Lake George, Fla. Unio minor Lua, Desc. 12 sp. Uniones, 1843; Tr. Am. Phil. poc., IX, 1646,p: 276; pl! xxix, hes 333"Obs., FY, 1848; a: 34, pl. xxx1x, fig. 3—Srmpson, Pr. U. S. Nat. Mus., XV, 1802, ‘p. 425; pl. Levit, fis. 2. Margaron (Unio) minor Lea, Syn., 1852, p. 31, 1870, p. 49. Lampsilis minor SIMPSON, Syn., 1900, p. 562. Unio stearnst B. H. Wricut, Check List, 1888. The pseudocardinals of this species are so peculiar that it would almost seem that it should group by itself. The general form, epidermis and nacre would seem to rather closely ally it to varieties of L. amygdalum. LAMPSILIS PAPYRACEA (Gould). Shell thin, obovate, subcompressed, with a low, posterior ridge, beaks rather low, placed well forward, sculptured with fine, doubly-looped ridges; surface with numerous irregular growth lines, the rest periods well marked, olive-green to rust- brown, the younger shells with numerous indistinct rays, the old shells often rayless; epidermis sometimes a little silky or cloth-like ; left valve with a long, low, irregular, compressed pseudocardinal, the front end of it higher, and showing indi- cations of being divided into two or three parts, with two well- developed laterals; right valve with a rather high, compressed pseudocardinal and a vestigial tooth above it, and one lateral; beak cavities shallow; muscle scars faint, the posterior ones scarcely discernible; nacre bluish-white, iridescent through- out, but especially so behind. Male shell full just behind the center of the base, ending behind in a blunt, often feebly bian- gulate point midway up from the base; female shell nearly evenly rounded behind and having a small, rounded marsupiak swelling placed well back. LAMPSILIS 147 Length (male) 43, height 26, diam. 15 mm. Length (female) 35, height 22, diam. 13 mm. Possibly not full grown. Type locality, Everglades, Florida. Unio papyraceus Goutp, Pr. Bost. Soc. N. Hist., II, 1845, p. 53-—sImpson, Pr. U. S. Nat. Mus., XV, 1892, p. 427, pl. PERV, f1g2 2. Margaron (Unio) papyraceus Lea, Syn., 1852, p. 38; 1870, p. 62. Lampsilis papyraceus SIMPSON, Syn., 1900, p. 562. A very fragile species, which appears. to be allied to L. amygdalum, but is thinner, more compressed and has a differ- ent texture. LAMPSILIS SINGLEYANA (Marsh). Shell small, subsolid, long elliptical or slightly obovate, not inflated ; beaks low, scarcely swollen, their sculpture not seen ; surface with delicate, irregular growth lines, shining, a rich tawny or tawny brown, sometimes darker banded; left valve with two low pseudocardinals, the hinder one a mere vestige, and two feeble laterals; right valve with one high, triangular, compressed pseudocardinal and one lateral ; beak cavities shal low, with two or three pits; muscle scars well marked; nacre soft, silvery-tinted, flesh-color, and more or less iridescent throughout, especially so behind. I have only seen a few spec~ imens of this pretty little shell, in which the male ends behind in a rounded point at one-half to three-fifths of the distance up from the base. The female shell has a rounded posterior point two-thirds of the way up from the base, and a small, rounded marsupial swelling at the extreme posterior part of the base. Length 32, height 20, diam. 12 mm. Putnam and Volusia Counties, Florida. Type locality, Palatka, Fla. Unio singleyanus Marsu, Joliet Weekly News (a newspaper), May 1, 1891; Nautilus, V, 1891, p. 29.—Simpson, Pr. U. 8. Nat. Mus., XV, 1892, p. 426, pl. Lxviml, figs. 4, 5. Lampsilis singleyanus SIMPSON, Syn., 1900, P. 563. 148 LAMPSILIS A very neat little shell, which seems to be somewhat closely allied to L. vesicularis. It is smaller and lighter colored than that species, and the posterior end of the female is somewhat obliquely truncated, while in vesicwlaris it is evenly rounded. There is a small shell in the National museum collection that is probably this, which is considerably rayed. Subgenus CARUNCULINA Simpson in Baker, 1898. © Carunculina Simpson in Baxer, Moll. Chicago, Pt. I, 1892, p. 109; Syn., 1900, p. 563. — ORTMANN, Ann. Car. Mus., VILL» tOr2y p. 337: Shell small, inflated, obovate, rather solid, covered with a thick, dark, often cloth-like epidermis, which is rayless or only feebly rayed; beak sculpture consisting of rather strong, con- centric ridges, which form, as a general thing, only a single, rounded loop in front, and are strongly curved upward behind. Pseudocardinals compressed, smooth on the inside, generally reflexed upward, somewhat torn on the edges. Shell quite commonly pointed posteriorly, that of the female truncated obliquely on post-hase. Animal with marsupinm consisting of a few large ovisacs (8 to 13) ; inner gill wholly or in part free from the abdominal sac; female often having a well-developed caruncle on the mantle below the branchial opening. Type, Unio texasensis Lea. Ortmann, (1. c.). considers this group a subgenus of Eury- nid. I,AMPSILIS TEXASENSIS (Lea). Shell somewhat elliptical, swbcompressed to inflated, beaks low, but full in inflated specimens, sculptured with from seven to nine sharp ridges, which fall in a single loop and are curved upward rather suddenly behind to the posterior ridge, from which they return towards the nucleus in nearly convergent raised lines ; posterior ridge well marked ; surface covered with a thick, brownish or blackish epidermis, which is often chest- nut tinted in the umbonal region; left valve with two com- pressed, ragged pseudocardinals, which are slightly reflexed, LAMPSILIS 149 and two curved laterals; right valve with one pseudocardinal and a vestige of another above it, with one lateral ; beak cavities shallow, with a few rather large scars; anterior cicatrices sep- arate; posterior cicatrices well impressed; nacre bluish-white to salmon, generally silvery iridescent and slightly thinner be- hind. The male shell is full and sometimes a little angular on the basal line just behind the center, and ends in a rounded or slightly biangulate point behind, midway up from the base. The female shell has a strongly developed, rather angular mar- supial swelling at some distance from the posterior end; from the swelling to the elevated posterior point it is truncated. It is smaller than the male shell. Length (male) 50, height 30, diam. 20 mm. Length (female) 40, height 28, diam. 20 mm. Texas, north to Kansas; Missouri; southern Illinois and In- diana; south through Tennessee, Alabama, Mississippi, and Louisiana. Type locality, DeWitt Co., Tex. Unio parvus Conrap, Monog. II, 1836, p. 20, pl. 1x, fig. 1— Han ey, Biv. Shells. 1843, p. 196, pl. xxut, fig. 3—SowERBY, Conch. Icon., XVI, 1866, pl. xxxv, fig. 186. Unio texrasiensis Lea, Pr. Ac. N. Sci. Phila., IX, 1857, p. 84. Unio texasensis Lea, Jl. Ac. N. Sci. Phila., IV, 1860, p. 359, pl. ux, fig. 184; Obs., XVIII, 1860, p. 41, pl. Lx1, fig. 184.— Cara, Pr Ind. Acad. Sc., 18096, p. 3, pl. v, figs. 38-40: Margaron (Unio) texasensis Lea, Syn., 1870, p. 49. Lambsilis texasensis SIMPSON, Syn., 1900, p. 563. Eurynia (Carunculina) texasensis ORTMANN, Ann. Car. Mus., WEN “1 RZ) p. 330. Unio texasianus Sowrrsy, Conch. Icon., XVI, 1866, pl. x1, fig. 218. Unio bairdianus Las, Pr. Ac. N. Sci. Phila., I, 1857, p. 102; Jl. Ac. N. Sci. Phila., TV, 1860, p. 361, pl. xt, fig. 186; Obs., VIII, 1860, p. 43, pl. Lx1, fig. 186. Margaron (Unio) bairdianus Lea, Syn., 1870, p. 49. 150 LAMPSILIS Umno beales Lea, Pr. Ac. N. Sci. Phila., VI, 1862, p. 169;' Jl. Ac. N. Sci. Phila., V, 1862, p. 204, pl, xxx, fig. 273; Obs., [Xx 1863.0, 26, pl. xxx, ain 274; Margaron (Unio) bealei Lea, Syn., 1870, p. 49. The species was described from a young, delicate male shell. Afterwards Lea described a young female as Unio bairdianus and still later Unio bealei from a larger, somewhat compressed male shell. Var. compressa Simpson. Shell subcompressed to compressed, rather thin, high and short, of an almost regular elliptical outline. Type locality, southwestern Texas. Lampsilis tevasensis var. contpressus SIMPSON, Syn., 1900, p. 564. All the specimens I have seen of the variety seem to be a little diseased, yet the form differs so widely from the type that I cannot believe it to be the result of pathologic influences. I,AMPSILIS MEARNSI Simpson. Shell short or long elliptical, considerably inflated, quite solid, with a well-developed, narrowly rounded post-basal ridge, with full elevated beaks, whose sculpture consists of a few singly looped, wavy ridges well drawn up behind; surface with irregular growth lines, greenish-yellow often with one or more dark green bands, usually the lower part of the posterior end of the shell is dark green, the patch ending quite abruptly in front. Sometimes there is one very broad green ray just be- hind the center and occasionally this is split into finer rays ; ep1- dermis rather silky; left valve with two compressed, slightly recurved pseudocardinals, and two long laterals, which extend to the pseudocardinals; right valve with one pseudocardinal, a faint one above it, and one lateral; beak cavities shallow ; muscle scars well impressed; nacre white, flesh-color or pale salmon, rich and silvery iridescent, thinner behind. The male shell is much larger and longer than that of the female; it has a slight, somewhat angular projection at the post-base, the pos- terior point is sharp and elevated midway up from the base, LAMPSILIS 151 and it is truncate on the lower hinder part. The female shell has a large, wide, rounded marsupial swelling behind the cen- tral base, and a sharp posterior point elevated two-thirds of the distance from the base. Length (male) 55, height 33, diam. 23 mm. Length (female) 40, height 27, diam. 21 mm. Type locality, vicinity of Fort Clarke, Kinney County, Tex. Lampsilis mearnst Simpson, Pr. Ac. N. Sci. Phila., 1g00, p. 75, pl. 1, fig. 4; Syn., 1900, p. 564. An attractive and remarkabie species, which is allied to L. texasensis, but differs in being more robust, more inflated, in having fewer and different ridges on the beaks, and in the color pattern. L. texvasensis is unicolored and dark; in mearnst there is almost always a very wide, broken ray or squarish blotch and one or more dark, concentric bands on a yellowish ground. LAMPSILIS PARVA (Barnes). Shell long elliptical or subcylindrical, generally a very little wider behind, inflated, subsolid, with full, but not high, beaks, which are turned forward over a narrow lunule, their sculpture consisting of seven or eight single-looped ridges, which are curved up more behind than in front, and return at the posterior end in converging lines to the nucleus ; posterior ridge wanting ; epidermis thick and cloth-like, blackish or fuscou's, often brown- ish in the umbonal region; left valve with two compressed, ragged, recurved pseudocardinals, and two delicate laterals ; right valve with one pseudocardinal, a minute one above it, and a single lateral; beak cavities and muscle scars shallow, nacre bluish-white, silvery and somewhat iridescent behind, slightly thickened in front. The male and female shells are much alike, the latter being more inflated and a little fuller at the extreme post-basal region. The male shell is usually evenly rounded behind, that of the female is often a little truncate and some- times has a blunt point above. The greatest diameter is behind the center of the shell, and the female is remarkable for some- times having the diameter greater than the height. 152 LAMPSILIS Length 32, height 17, diam. (of male) 13 and (of female) 21 mm. Mississippi River drainage generally ; southwest to central Texas; western New York; southern Canada; and Michigan. Type locality, Fox River. Unio parvus BarRNES, Am. Jl. Sci., VI, 1823, pl. x11, fig. 18 (outline).--Pritipp1, Abbild., I, 1845, p. 10, pl. 1, fig. 4.— Kuster, Conch. Cab. Unio, 1852, p. 33, pl. v, fig. 5. Margarita (Unio) parvus Lea, Syn., 1836, p. 28; 1838, p. 21. Margaron (Umo) parvus Lia, Syn., 1852, p. 31; 1870, p. 49. Lampsilis parvus BAKER, Moll. Chi., Pt. I, 1898, p. 109, pl. x11, fig. 3-—SIMPSON, Syn., 1900, p. 564. Mya parva Eaton, Zool. Text-Book, 1826, p. 222. Eurynia (Carunculina) parva OrtTMANN, Ann. Car. Mus., VIL} 1912, p./3368. This species has often been confounded with L. terasensis, to which it is not very closely allied. Even Dr. Lea placed several specimens of the latter with his parva. It differs from all other members of the group in having the female sheli greatly inflated, and in having the shells of both sexes almost evenly rounded behind. Generally it is one of the smallest of the Uniones, but it sometimes attains a length of two inches. LAMPSILIS HALEIANA (Lea). Shell long elliptical or obovate, subinflated, scarcely subsolid ; beaks somewhat full and raised above the dorsal outline, sculp- tured with seven or eight strong, singly looped ridges, which are wel curved up behind; sometimes the beak sculpture is slightly doubly looped; surface with numerous low, irregular, concentric ridges, rayless or nearly so, and covered with an olive-green or brown epidermis; left valve with two compress- ed. slightly recurved pseudocardinals, and two curved laterals ; right valve with one compressed pseudocardinal and one lat- eral; beak cavities and adductor scars shallow; nacre silvery, bluish-white. iridescent, and a little thinner behind. Male shell a little full and subangular in the post-basal region with a rounded point behind midway up from the base; female shell shorter, somewhat obovate, with a full, rounded marsupial LAMPSILIS 153 swelling, just behind the middle of the base, and the posterior end blunt, rounded, and a little elevated. Length (male) 70, height 40, diam. 25 mm. Length (female) 57, height 33, diam. 22 mm. Alexandria, Louisiana; eastern Texas. Type locality, Mississippi River, thirty miles above New Orleans, Ia. . Unio haleianus Lwa, Pr. Am. Phil. Soc., II, 1842, p. 224; Tr. Aime ail: .Soe VILL 18425 p.'247, ploxxvi, fig. 63; ‘Obs., III, 1842, p. 85, pl. xxvu, fig. 63.—CuHENU, III. Conch., 1858, pl. xxv1, figs. 6, 6a, 6b.—? Reeve, Conch. Icon., XVI, 1865, pl. xxiv, fig. 116. Margaron (Unie) haleianus Lea, Syn., 1852, p. 31; 1870, p. 49. Lampsilis haleianus Stmpson, Syn., 1900, p. 564. This species is close to L. terasensis, but is larger and thin- ner, and the epidermis is usually lighter colored. The female shell is more rounded behind than it is in tevasensis. Specimens have been found in Old River, Victoria County, Texas, which agrée very well with halciana in size, form and solidity, but which have a darker epidermis and a pale, dirty salmon nacre. I cannot be certain which species they should be referred -to. The 1. haleiana sometimes has doubly-looped beak sculpture. LAMPSILIS GLANS (Lea). Shell short elliptical, rather solid, inflated, with a low, round- ed posterior ridge, and a decided lunule, with full, high beaks, having irregular, subnodulous ridges, which curve up somewhat behind, and are nodulous at the posterior ridge, returning by converging lines to the embryonic shell ; surface with irregular, growth lines, rayless, covered with a dark brownish, thick epi- dermis; left valve with two irregular, ragged pseudocardinals, which are often united by a ridge at their upper sides, and two laterals; right valve with one pseudocardinal and sometimes a vestige of another above it, and two laterals, or with one and a faint second one below it; beak cavities shallow ; muscle scars well impressed ; nacre generally purple and lighter on the bor- der, though sometimes creamy white, suddenly becoming thin- 154 LAMPSILIS ner behind, where it is usually iridescent. The male shell is short elliptical or subrhomboid. the blunt, rounded posterior point being at or below the middle of the height of the shell. The female shell is shorter and a little more inflated; it has a decided angular marsupial swelling at the posterior base, and the posterior point is elevated two-thirds of the way up from thé base of the shell. Length (male) 36, height 24, diam. 17 mm. Length (female) 32, height 24, diam. 18 mm. Ohio River drainage; Warsaw, Indiana; (probably St. Law- rence drainage) ; southern Michigan; White River, Carroll County, Arkansas (Call) ; Etowah River, Georgia. Type locality, Ohio River. Unio glans Lea, Tr. Am. Phil. Soc., 1834, p. 82, pl. xvi, fig. (2; Obs., I, 1834, p. 92, pl. vit, fig. 12—Conrap, Monog., IT, 1836, p. 21, pl. 1x, fig. 2—HANLEY, Biv. Shells, 1843, p. 196, pl. xxu, fig. 33—Kuster, Conch. Cab. Unio, 1852, p. 37, pl. v1, fig. 3.—Cuenu, Ill. Conch., 1858, pl. vu, figs. 9, ga, 9b. —Sowersy, Conch. Icon., XVI, 1866, pl. xxxv1, fig. Igo. Margarita (Umo) glans LEA, Syn., 1836, p. 28; 1838, p. 21. Margaron (Unic) glans Lea, Syn., 1852, p. 31; 1870, p. 49. Lampsilis glans Simpson, Syn., 1900, p. 565. j Eurynia (Carunculina) glans OrtMANN, Ann. Car. Mus., VIL, 1912;4p.-330: This species is usually quite distinct from all others. It is shorter, solider and more inflated than germana and differs in having a purple nacre; it is very much shorter than cylin- drella and the female is shaped differently from either of the above species. Occasional shells have a whitish nacre. LAMPSILIS GERMANA (Lea). Shell long elliptical or a little rhomboid, that of the female slightly obovate, subsolid, subcompressed to subinflated, with a rounded posterior ridge and small, somewhat compressed, but rather elevated beaks, their sculpture not seen; surface finely concentrically sculptured, rayless, covered with a black or brown, thick epidermis ; left valve with two rather ragged, com- LAMPSILIS 155 pressed pseudocardinals and two. straight laterals; right valve with one pseudocardinal and sometimes a feeble tooth above it, with one lateral; beak cavities shallow but compressed ; muscle scars shallow; nacre bluish or purplish-white, richly iridescent behind, scarcely thicker in front. ‘The male and female shells differ but little, the former is sometimes a little rhomboid, the rounded posterior point being nearest the base ; the female shell has a feeble, but long, marsupial swelling, and the posterior point is about midway up. Length 38, height 22, diam. 15 mm. Type locality, Coosa River. Also Big Prairie Creek, Ala- bama. Inio germanus Lea, Pr. Ac. N. Sci. Phila., V, 1861, p. 40; Jl. Ac. N. Sci. Phila., VI, 1866, p. 49, pl. xtx, fig. 54; Obs., XI, [S07 P53, Pl. KIX, He. 54: Margaron (Unio) germanus Lia, Syn., 1870, p. 49. Lampsilis germanus SIMPSON, Syn., 1900, p. 565. Unio granulatis Lea, Pr. Ac. N. Sci. Phila., V, 1861, p. 60. Unio granulatus Lea, Jl. Ac. N. Sci. Phila., VI, 1866, p. 48, pl. xvI, fig. 46; Obs., XI, 1867, p. 52, pl. xv1, fig. 46. Margaron (Umo) granulatus Lea, Syu., 1870, p. 40. This species has no strong characters, but it is less solid and inflated than L. corvunculus and I. cylindrella, and it differs from the latter in the color of the nacre. It is darker colored and much more sulcate than 1. cromwiellit. LAMPSILIS CYILINDRELLA (Lea). Shell long elliptical, with the dorsal and ventral lines nearly parallel, solid, subinflated, with rather full, but not high, beaks, their sculpture not seen; posterior ridge low or wanting ; sur- face tawny, rayless, with a thick epidermis ; left valve with two stumpy pseudocardinals and two laterals; right valve with one pseudocardinal, and one lateral, which sometimes has a slight ridge at its inner base; beak cavities shallow, with one or two pits; muscle scars well impressed ; nacre whitish at the border, rich coppery within, thinner and iridescent behind. The female 156 I.AMPSILIS shell differs but very little from that of the male, having a faint marsupial swelling near the posterior part of the base and both are nearly evenly round behind. Length 37, height 20, diam. 16 mm. Tennessee River drainage. Type locality, Duck River, Tenn.; Swamp Creek, Whitfield Co., Ga.; northern Alabama. Unio cylindrellus Lea, Pr. Ac. N. Sei. Phila., XII, 1868, p. 144 ; JL. Ac. N. Set. Phila., VL, 1860,. 9: 308) ph xiv, Teo rer: —Obs.. XII, 1869, p. 68, pl. xivii, fig. 121. Margaron (Unio). cylindrellus Lea, Syn., 1870, p. 49. Lampsilis cylindrellus SIMPSON, Syn., 1900, p. 565. The solid, long, almost cylindrical shell and the coppery nacre, bordered with lighter color, distinguish this from allied species. The specimens I take to be females differ but very little from the males, being only a very little fuller in the post- basal region. LAMPSILIS MGESTA (Lea). Shell long elliptical or subrhomboid, subinflated, rather solid, with a very faint posterior ridge; beaks probably full; surface concentrically striate, having an olive-brown epidermis, rayless ; left valve with two stumpy pseudocardinals and two short lat- terals: right valve with one pseudocardinal and one lateral: beak cavities not deep, having a few deep pits; nacre dirty, dark purple, somewhat thinner and iridescent behind. Length 47, height 26, diam. 18 mm. Type locality, French Broad River, Tennessee. Unio mestus Lea, Pr. Am. Phil. Soc., II, 1841, p. 82; Tr. Am. Phil. Soc. VII, 1842, .p:.244,-pl. xxvip fen Gos Ons, LUE 1842, p. 82, pl. xxvi, fig. 60.—CreEny, Ill. Conch., 1858, pl. XXVIII, figs. 3, 3a, 3b.—Kuster, Conch. Cab. Unio, 1861, p. 226, pl. LX XVI, fig. 5. Margaron (Unio) mestus Lea, Syn., 1852, p. 31; 1870, p. 49- Lampsilis mastus SIMPSON, Syn., 1G00, p. 565. LAMPSILIS | 157 Only two specimens, both in the Lea collection, and one of them the type, have been seen by the writer. Both are dead and badly eroded. One is somewhat rhomboid, the upper pos- terior part being slightly truncated ; the post-basal point is wide- ly rounded. The other is nearly evenly rounded behind and may be a female, though it has no perceptible post-basal swell- ing. I cannot be certain as to the systematic position of this species. Its texture and color are much like those of L. vanux- emensis, but the form is most like that of members of the parva group. It is larger and much darker colored than J,. cylindrella, it is larger and solider than germana, and has a darker nacre. LAMPSILIS CROMWELL (Lea). Shell somewhat obovate, subsolid, subcompressed or but slightly inflated, with a low, rounded posterior ridge; beaks rather high and sharp, sculptured beautifully with eight or more regularly curved ridges, their curve being shorter than that of the growth lines; surface with fine growth lines, green- ish-yellow, sometimes clouded with green, often having two light colored rays on the posterior slope, and concentrically banded with lighter color; epidermis only moderately thick ; left valve with two compressed, ragged peudocardinals and two curved laterals; right valve with one irregular pseudo- cardinal and sometimes a double lateral; beak cavities shallow : posterior muscle scars faint; nacre white or lurid, silvery, iri- descent and a little thinner behind. Male shell a little rhom- boid or evenly rounded behind ; female shell with a feeble, sub- angular marsupial swelling, the shell behind it is truncate up to the somewhat elevated posterior point. Length 27, height 17, diam. 12 mm. Western Georgia and southeastern Alabama. Type locality, Kiokee Creek, Albany, Dougherty Co., Ga. Umio cromwellu Lea, Pr. Ac. N. Sci. Phila., 1X, 1865, p. 89; Hike. Sciicehila, V1; 1860, p41 258, pl.xxxt, fig. 73; Obs., AL, 1860; pis; ploxxxs, fic. 73: 158 LAMPSILIS Margaron (Unio) cromwellu Lea, Syn., 1870, p. 49. Lampsilis cromwellii Simpson, Syn., 1900, p. 565. Unio margints Lea, Pr. Ac. N. Sci. Phila., IX, 1865, p. 89; Jl. Ac. Nese. Phila., VI; 1860>p. 225, pl xxxi, fic. Go; Obs. ATT) 1860, G05, pl. Xxx1; fis 60. Margaron (Unio) marginis Lea, Syn., 1870, p. 49. A smoother, lighter colored shell than that of corvunculus, and the nacre is not purple. The beak sculpture consists of semicircular ridges, while those of corvunculus follow the growth lines. This and Unio marginis seem to me to be abso- lutely identical. LAMPSILIS CORVUNCULUS (Lea). Shell elliptical or obovate, subcompressed or scarcely inflated, rather thin to subsolid, with low beaks, which are sculptured with a few singly-looped ridges, which nearly follow the growth lines; posterior ridge wanting; surface with irregular growth lines, and covered with a thick, brownish or blackish epidermis ; left valve with two somewhat compressed ragged pseudocar- dinals which are partly joined above, and two low, curved lat- erals; right valve with one pseudocardinal and a vestige of a second above it, with one lateral having a groove along its lower face; beak cavities shallow ; posterior scars faint ; nacre purple, iridescent and slightly thinner behind. The male shell is somewhat rhomboid, but nearly evenly rounded behind ; that of the female has a small, angular marsupial swelling not far from the posterior end, and is obliquely truncated below the elevated posterior point. Length 32, height 20, diam. 12 mm. Western Georgia; Village Creek, Jefferson County, Ala- bama: Lake Ashby, Florida. Type locality, Swamp Creek, Whitfield County, Georgia. Unio corvunculus Lua, Pr. Ac. N. Sci. Phila., XII, 1868, p. 144; Jl. Ac. N. Sci. Phila., VI, 1869, p. 314, pl. 1, fig. 127; Obs.; XH, 1860;.p: 74, pl.2, fis) t27, LAMPSILIS 159 Margaron (Unio) corvunculus Laa, Syn., 1870, p. 49. Lampsilis corvunculus Simpson, Syn., 1900, p. 566. Thinner, shorter and more compressed than J, paula, and it has a purple instead of a whitish nacre. The female does not have the small radial ridge that is found on that of paula. LAMPSILIS PAULA (Lea). Shell long elliptical, rather solid, inflated; beaks full but not high, sculptured, with a few singly-looped ridges, which are curved up quite sharply behind; surface covered with irregular growth lines, which sometimes form strong concentric ridges ; in the young shells the epidermis is often green with one or two light rays on the posterior slope and with concentric yel- lowish bands; in the adult shells it is thick and black ; left valve with two low, irregular, ragged pseudocardinals, which are often partly joined together and are sometimes slightly reflexed, and two laterals; right valve with one pseudocardinal, some-. times with a vestige of a second, and one lateral ; beak cavities shallow ; muscle scars well marked : nacre dirty white or lurid, iridescent behind. Male shell nearly evenly long elliptical, rounded before and behind, slightly thicker in front: female shell irregularly long elliptical; the posterior base but slightly swollen, angular, and there is often a small radiating ridge leading from the beaks to this part of the shell; behind this it is obliquely truncate to the posterior point, which is more than midway up from the base; the hinder part of the shell is much thinner than the front part. Length (male) 37, height 22, diam. 16 mm. Length (female) 36, height 21, diam. 20 mm. Flint and Chattahoochee Rivers, Georgia. Type locality, Chattahoochee River, Columbus, Ga. Unio paulus Lea, Pr. Am. Phil. Soc., I, 1840, p. 287; Tr. Am. Phil. Soc., VIII, 1842, p: 213, pl. xv, fig. 29; Obs., IIT, 1842, p. 51, pl. xv, fig. 29.—CHENu, Ill. Conch., 1858, pl. xxvu, figs. 5, 5a, 50—Kuster, Conch. Cab. Unio, 1861, p. 260, pl. LX eRVIT, fo. 6, Margaron (Unio) paulus Lea, Syn., 1852, p. 31; 1870, p. 49. 160 LAMPSILIS Lampsilis paulus SiMPSON, Syn., 1900, p. 566. Eurynia (Carunculina) paula OrrmMann, Ann. Car. Mus., VIII, 1orap. 330. Umio corvinus Lea, Pr. Ac. N. Sci. Phila., XII, 1868, p. 144; Jl. Ac. N. Sci. Phila., VI, 1869,"p. 310, pl. xivim, fig. 123; Obs., XII, 1869, p. 70, pl. xvii, fig. 123. Margaron (Unio) corvinus Lea, Syn., 1870, p. 49. The type of Lea’s paulus is a male shell and that of his corvinus 1s a female of the same species. ‘The post-basal swell- ing of the female scarcely projects below the base line of the shell, but it is angular and this with the peculiar radial ridge leading over it as well as the sudden thickening of the front part of the shell are good distinguishing characters. The male shell is much like that of 1. germana, but is solider, more in- flated and darker. LAMPSILIS PULLA (Conrad). Shell long elliptical or subrhomboidal, subinflated, especially at the center, rather solid; dorsal and ventral lines almost par- allel; beaks moderately full, but not high, eroded in the speci- men figured; epidermis dark olivaceous; left valve with two pseudocardinals and two laterals ; right valve with one pseudo- cardinal and one lateral; nacre chocolate-purple, iridescent be- hind; beak cavities capacious. Length 33, height 17, diam. 12 mm. Type locality, Wateree River, South Carolina. Also, Warm Springs, North Carolina. Unio pullus Conrap, Monog., XI, 1838, p. 100, pl. Liv, fig. 2.— Kuster, Conch. Cab. Unio, 1862, p. 270, pl. xcl, fig. 2. Margaron (Unio) pullus Lea, Syn., 1852, p. 31; 1870, p. 49. Lampsilis pullus Stmpson, Syn., 1900, p. 566. In form this is a good deal like L. masta, being obliquely truncated on the posterior slope and rounded at the posterior basal-point. It is a smaller species, and, according to Conrad. it must have a much darker nacre, which is iridescent behind, while that of masta does not seem to be. It differs from cyl- indrella in being much darker, and in having uniformly purple LAMPSILIS I6L nacre, while that of the last named species is bordered with white. The shell figured by Conrad is probably a male. Ac- cording to Conrad its greatest diameter is at the middle of the shell, and from that point it rapidly tapers toward each end. Conrad’s figure is a poor one, and | can not be positive just where the species should be placed, but incline to think it a member of the tevasensis group. lea has a shell, which he calls the Unio pullus of Conrad, which came from Ravenel, labeled “S. Carolina,” but which, I think, is not this, but some species of the swbrostrata group. It is quite probable that pzdla is the same as I.ea’s corzuncula. Subgenus Proprera Rafinesque, 1819. Proptera RAFINESQUE, Jl. Phys. Chim. Hist. Nat., LXXXVIII, 1819, p. 426.—SIMPSON, Syn., 1900, p. 566.—ORTMANN, Ann Cars Mus, ViLIL,:1912; p: 330. Metaptera RariNesQue, Ann. Gen. Sci. Phys. Brux., V, 1820, - Pp. 299. Shell usually large, gaping at the anterior base and edge of the dorsal slope, winged along the dorsal region when young and often when adult; beak sculpture feeble, consisting, when developed, of an anterior and posterior loop, the former often wanting ; the latter sometimes becomes slightly nodulous ; ep1- dermis generally brown, often cloth-like when fresh, rayless or feebly rayed; teeth rather compressed, pseudocardinals fre- quently imperfect or nearly wanting; laterals remote; anterior muscle scars often complicated; dorsal scars consisting of a row of from four to thirty distinct, often deep, impressions, running from the cavity of the beak obliquely downward an- teriorly; nacre purplish. Animal with large branchiz; mar- supium consisting of numerous, generally fine, ovisacs, which are often somewhat radial; mantle thickened and distinctly double on the border, often papillose behind, where the outer ‘fold develops into a thickened flap; branchial opening with irregular teeth ; anal opening smooth or only slightly crenulate Type, Unio alata Say. Ortmann, (1. c.), raises this group to generic rank. 162 LAMPSILIS Group of Lampsilis alata. Shell obovate, strongly winged, subsolid, with a slight pos- terior and superposterior ridge; epidermis thick, dark, show- ing irregular growth lines; hinge teeth generally well devel- oped; nacre dark purple; female shell greatly developed in post-basal region. Animal having the ovisacs very. numerous and fine; marsupium large; inner gills united to abdominal sac throughout. LAMPSILIS ALATA (Say )- Shell large, inequilateral, somewhat obovate, rather com- pressed, subsolid, narrowed in front where it is rounded in adult shells, but in the young shell it has a small angular dor- sal wing; beaks low, compressed, their sculpture very faint, consisting of feeble, broken ridges or sometimes of nodules, which show a slight tendency in the direction of double loop- ing; there is a low but rather pinched up ridge running from the beaks down the posterior slope of the shell to its edge, and above this it is carried up into a high triangular dorsal wing, which is beautifully developed in young shells, but usually is broken away in old ones; below the upper posterior ridge there is often a second ridge, which reaches to the extreme posterior part of the shell; posterior end of the shell wide and rounded; surface with irregular, concentric sculpture, brownish, blackish or olive-green, sometimes faintly rayed in young specimens; in adult shells the unbonal region is reddish-brown. Left valve with ragged, generally compressed pseudocardinals, with sometimes a vestige of a third above the anterior one, and two remote, curved laterals; right valve with two pseudocardinals, the lower the larger and one high, truncated lateral; muscle scars large, the anterior appressed. posterior scars faint; beak cavities shallow; dorsal scars numerous, in a row running downward; ligament and es- cutcheon large; nacre coppery-purple, somewhat thickened in front. The female shell has a large, rounded marsupial swelling at the extreme post-basal part and is generally sub- LAMPSILIS 163 truncate behind; the male shell is less full in the post-basal region, and is nearly rounded behind. Length 160, height to point of broken wing 120, diam. 40 mm. Entire Mississippi drainage as far south as Arkansas; St. Lawrence drainage; Red River of the North. Type locality not given. Unio alaius Sav, Nich. Encyc.; IJ; 1817, pl. 1v, fig. 2—H1- DRETH, Am. Jl. Sci., XIV, 1828, p. 285, fig. 17—Conrap, Monog., VII, 1836, p. 57, pl. xxx1—Sowerpsy, Conch. Man., 1839, fig. 147.—Reeve, Conch. Syst., I, 1841, p. 118, pl. LXXxtx, fig. 8—C. B. Apams, Thompson’s Hist. of Ver- mont, 1842. p. 166, fig;.L. and F. W. Shells of Vermont, 1842, p. 16, fig—Potikz and Micuaun, Gall. Moll., 1844, p. 146, pl. ivi, fig. 2—Kuster, Conch. Cab., 1852, p. 15, pl. 1, fig. 1—CueEnu, Man., 1859, II, p. 143, fig. 708.—SoweEr- By, Conch. Icon:, XVI, 1866, pl. xtiv, fig. 242. : Margarita (Unio) alatus Lea, Syn., 1836, p. 11; 1838, p. 13. Margaron (Unio) alatus Lea, Syn., 1852, p. 19; 1870, p. 28. Lampsilis alatus Baker, Moll. Chicago, Pt. 1, 1898, p. 97, pl. XVIII.—SIMPSON, Syn., 1900, p. 567. Unio alata LAMARCK, An. sans Vert., VI, 1819, p. 76. Mya alata, Eaton, Zool. Text-Book, 1826, p. 219.—Woop, In- dex Test. (Rev.), 1856, p. 199, pl. 1, supp. fig. 3. Symphynota alata Lea, Tr. Am. Phil. Soc. III, 1830, p. 448: Obs., I, 1834, p. 62. Lymnadia alata Swatnson, Treat. on Mal., 1840, p. 265, fig. 48. Mysca alata Swainson, Exotic Conch., 2d ed., 1841, p. 28, pl. VII. Metaptera alata Stimpson, Shells of N. Eng., 1851, p. 14. Proptera alata ORTMANN, Ann. Car. Mus., VIIT, 1912, p. 333. ? Metaptera metaptera RAFINESQUE, Ann. Gen. Sci., Brux, V, 1820, p. 300, pl. Lxxx, figs. 20-22——CuHeENu, Bib. Conch., mst set., Te 1845; -p. 15, ple 1, figs. 20-22. 164 LAMPSILIS Var. poulsoni (Conrad). More solid and inflated than typical shells and narrower in front. The two posterior ridges are quite distinctly developed, the outIne from the hinder end of the post-dorsal wing to the end of the upper ridge is incurved, and that between the two ridges is often incurved. Its surface is rougher than in the type, and the teeth are rather heavier. This may almost be considered a distinct species, but it is connected with typical forms by an abundance of material in the Tennessee region. Length 123, height 8o, diam. 43 mm. Alabama and Tombigbee Systems. Type locality, Black Warrior River, Ala. Unio poulsoni Conrav, New F. W. Shells, 1834, p. 25, pl. 1; p. 71.—CHENU, Bib. Conch., Ist ser., III, 1845, p. 15, pl. 1 fig. 7. Symphynota poulsoni Frrussac, Guer. Mag., 1835, p. 25. Lampsilis alatus var. poulsom SIMPSON, Syn., 1900, p. 568. This species is solider, darker colored and has darker nacre than L. gracilis and levissima, with which it is most often asso- ciated. The female shell is more produced in the post-basal region than in either of those species. It is less inflated and ponderous than 1. purpurata. LAMPSILIS COLORADOENSIS (Lea). Shell large, irregularly obovate, subsolid, with a rather dis- tinct posterior ridge and two slightly elevated, dark, radial ridges on the posterior slope; beaks somewhat full and high, their sculpture consisting of corrugated, doubly-looped ridges ; posterior wing broken off down to the large ligament in half grown to adult shells; surface with irregular growth lines, pale smoky-brown, nebulously banded and rayed with olive; left valve with two ragged, elevated, subcompressed pseudocar- dinals, the anterior the larger, and two short, remote laterals ; right valve with two pseudocardinals, the upper smaller, and one high, truncated lateral ; beak cavities moderately deep, with an irregular row of pits running towards the anterior base; anterior scars deep, separate; posterior scars large and shal- LAMPSILIS 165 low ; nacre purplish, thicker in front. The male shell is some- what truncated at the post-dorsal part and is full in the post- basal region, ending in a blunt point just below the medium line. The female shell, of which I have only seen young specimens, is fuller in the post-basal region than that of the male, and is nearly rounded behind. Length 123, height 76, diam. 40 mm. Eastern Texas. Type localitv, Rio Colorado, ‘Texas. Umo coloradoensis Les, Pr. Ac. N. Sci. Phila., VIII, 1856, p. tog gio Ae. Ni Ser Phila; 111, 1858; p..314, pl: xxx1, fig. 290; Obs., VI, 1857, p. 34, pl. xxx1, fig. 29. Margaron (Unio) coloradoensis Lea, Syn., 1870, p. 41. Lampsilis coloradoensis Stimpson, Syn., 1900, p. 568. Probably only a mere variety of purpurata. It is less inflated, lighter colored, and is less solid than that species. I have only seen three or four authentic specimens and hardly feel like making it a variety of purpurata without more evidence. LAMPSILIS ROVIROSAI Pilsbry. Shell large, moderately solid, obovate, inflated, with strongly marked, somewhat sulcate growth lines; epidermis dark brown or blackish, with very fine concentric wrinkles; beaks moder- ately elevated, full; ligament large; posterior ridge rounded and above it on the posterior slope there is a radial depression; hinge line slightly curved; left valve with two small, slightly ragged, subtriangular pseudocardinals and two short, heavy, remote laterals; right valve with two pseudocardinals, the up- per rudimentary, and a high, striated lateral; anterior scars deep and smooth, the adductors large; posterior scars large, nearly semicircular; nacre soft flesh-color in the cavity of the shell, whitish at the border, iridescent behind; beak cavities moderately deep, with a row of muscle scars running towards the anterior base. Hinge line narrow between the two sets of teeth, and occupied with epidermal matter. Length 112, height 72, diam. 45 mm. Laguna de Atasta, near San Juan Bautista, Mexico. 166 LAMPSILIS Unio (Lampsilis) rovirosai Pirsspry, Nautilus, XIII, 1goo, p. 140. Lampsilis rovirosai SIMPSON, Syn., 1900, p, 508.—PrLspry, Pr. Ac. N. Sci. Phila., 1903, p. 788, pl. LIVv, figs. 1, 1a. Only the type in the Philadelphia Academy of Sciences 1s known, and this is somewhat narrowed in front, with a long and rather full, rounded post-basal swelling, which does not reach to the posterior end. ‘The posterior point is blunt and rounded, two-thirds of the way up from the base. It is nearest to L1,. purpurata but is more decidedly sulcate, the nacre is much lighter colored, and the beaks are lower. The beaks of the specimen seen are so hadly eroded that the sculpture is de- stroyed. This is probably a female, and the post-basal swell- ing is larger and farther from the posterior’ énd than it is in purpurata. LAMPSILIS PURPURATA (Lamarck). Shell very large, somewhat obovate, inflated, with full, high beaks, having very faint, corrugated sculpture, scarcely winged in front, with a low, angular wing behind; there are two or sometimes three low, radiating ridges on the posterior slope; surface nearly smooth or somewhat sulcate, covered with a shining, blackish epidermis; ligament large and long, gener- ally exposed in adult shells ; left valve with two subcompressed to solid, ragged pseudocardinals and two strong, remote lat- erals, the hinge line rounded between the two sets of teeth; right valve with two pseudocardinals, the lower the larger, and one strong, trurcated lateral; beak cavities rather deep, with a row of deep scars running towards the anterior base ; muscle scars large, the anterior deep and smooth, the posterior scarcely impressed; nacre rich, dark purple, somewhat irides- cent behind, much thicker in front. Male shell full at the pos- terior base, rounded and obtusely biangulate behind above the median line: the female shell has a wide, rounded, marsupial swelling far behind, and is decidedly truncate posteriorly. Length 170, height 110, diam. 67 mm. Length (female) 130, height 90, diam. 58 mm. LAMPSILIS 167 Eastern ‘lexas, north to Kansas, through southern Missouri, western Tennessee, to the Alabama River drainage. Type locality, “Africa’’!! Unio purpurata L.AMARCK, An. sans Vert., VI, 1819, p. 71. Unio purpuratus Lea, Obs. I, 1834, p. 199.—Han ey, Biv. Shells, 1843, p. 208, pl. xxur, fig. 5—Kusrer, Conch. Cab. Unio, 1861, p. 185, pl. L1x, fig. 1—Rerrve, Conch. Icon., XVI, 1865, pl. xxiv, fig. 115.—CaL, Tr. Ac. Sci. St. Louis, VII, No. 1, 1895, p. 38, pl. v. Margarita (Unio) purpuratus Lea, 1836, p. 39; 1838, p. 25. Margaron (Unio) purpuratus Lea, Syn.. 1852, p. 38; 1870, p. OL. Lampsilis purpuratus SIMPSON, Syn., 1900, p. 568. Proptera purpurata ORTMANN, Ann. Car. Mus., VIII, 1912, p. 334: Unio ater 1a, Tr. Am. Phil. Soc., III, 1830, p. 426, pl. vu, fir. 9; Obs. 1, 1834, p. 40, pl. vu, fig. 9 —CHENU, III. Conch., 1956, pl.x; figs. te, 10: Unio atra DesHayes, Enc. Meth., II, 1830, p. 582. Unio lugubris Say, Am. Conch., V, 1832, pl. xuim; VI, 1834. Unio poulsoni Sowersy, Conch. Icon., XVI, 1866, pl. 11, fig. 270. Umo-dolosus Lea, Pr. Ac..N. Sci. Phila., 1V, 1860, p. 307;, JI. AGoNe oc enila.. V, 1802, p..75, pi 1x, fig..224'; Obs:, VIII, 1862, p. 79, pl. 1x, fig. 224—Sowersy, Conch. Icon., XVI, 1866, pl. xu, fig. 228. Margaron (Unio) dolosus Lea, Syn., 1870, p. 61. A magnificent shell, the finest and probably the largest Lamp- silis. It seems to take the place of ZL. alata in the southwest. It is much more inflated than that species, is darker and more glossy, has a lower dorsal wing and richer nacre. I,AMPSILIS PERMISCENS (Lea). Shell irregularly obovate, thin, subinflated, gaping at the posterior slope and anterior base, with moderate posterior wing and a full, widely rounded posterior ridge; beaks low and compressed, their sculpture not seen; epidermis smooth, smoky, olive to blackish, feebly rayed, darker on the posterior 168 LAMPSILIS slope: left valve with a long, low, feebly developed pseudo- cardinal, which is somewhat divided in the middle, and two remote, delicate laterals; right valve with a single compressed pseudocardinal and one high, truncated lateral; beak cavities shallow, with a row of pits; muscle scars superficial; nacre blue, becoming somewhat lurid at the beak cavities. The only shell I have seen is the type, which is probably a young female. It is somewhat rhomboid behind and well developed into a mar- supial swelling at the extreme posterior base. The front end of the shell is narrow. Length 55, height 37, diam. 20 mm. Type locality, Tombigbee River, Columbus, Mississippi. Unio permiscens Lea, Pr. Ac. N. Sei. Phila., HI, 1859, p. 1125 Jl. Ac. N. Sci. Phila., V, 1862, p. 102, pl. xvi, fig. 251; Obs., VIII, 1862, p. 106, pl. xvu, fig. 251. Margaron (Unio) permiscens Lea, Syn., 1870, p. 61. Lampsilis permiscens StMPSON, Syn., 1900, p. 569. This is undoubtedly a young shell and not in the best condi- tion. It is not unlikely that it is a young L. purpurata. LAMPSILIS GOULDII (Lea). Shell almost regularly elliptical, a very little wider behind than in front, subsolid, not inflated, with a low posterior ridge and two radiating, slightly raised, darker ridges above it ; beaks probably not high, so eroded in the only specimen seen that nothing can be made out from them; posterior base a little full; surface with irregular growth lines, covered with a dark brown epidermis; left valve with two small pseudocardinals, the an- terior slightly compressed, the posterior stumpy, and two re- mote, curved laterals ; right valve with one pseudocardinal and one lateral: beak cavities not deep; muscle scars shallow, the hinder faint ; nacre bluish-white, slightly thicker in front. Length 50, height 29, diam. 17 mm. Type locality, Tuscaloosa, Alabama. Unio gouldii Lea, Pr. Am. Phil. Soc., IV, 1845, p. 165; Tr. Am. Phil. Soc., X, 1848, p. 76, pl. v1, fig. 16; Obs., IV, 1848, Dp: 50, pk Vi, me. 16. Margaron (Unio) gouldii Lua, Syn., 1852, p. 29; 1870, p. 46- Lampsilis gouldii Stmpson, Syn., 1900, p. 569. LAMPSILIS 169 I only know of a single specimen of this species, the type, and this consists of two fairly well matched, but badly eroded, dead valves, which probably come from young shells. The beak cavities each have a lurid bronze blotch, but do not ex- hibit, so far as I can see, any pits. ‘The posterior end of the shell is slightly pointed and biangulate on the median line. The radial, dark ridges on the posterior slope are much like those of members of this group, and the shell has some resem- blance to a young wmbrosa, but I cannot be sure where it belongs. Group of Lampsilis saladoensis. Shell smooth, obovate, inflated, inequilateral, rounded be- hind, thin, slightly thicker in front; beaks somewhat promi- nent, nearly smooth; epidermis yellowish-olive, shining, rayed ; there is a slight carina high up on the posterior slope; pseudo- cardinals small, lamellar and oblique; laterals lamellar and curved ; anterior cicatrices distinct and well impressed; poste-- rior cicatrices confluent ; dorsal cicatrices under the plate, be- tween the pseudocardinals and laterals ; nacre bluish-white and iridescent. Animal unknown. LAMPSILIS SALADOENSIS (Lea). Shell obovate, rather thin, much inflated, with full, high beaks almost destitute of sculpture, with a full, somewhat double pos- terior ridge ; rounded and narrowed in front with a slight post- dorsal wing; surface pale yellowish-green in the young shell, olive-green when older, ‘with numerous feeble, ;wide rays on the posterior half of the shell, which are evenly spaced ; epidermis smooth and shining; left valve with a single, somewhat com- pressed pseudocardinal which may be bifid, and two remote, delicate laterals; right valve with two nearly equal pseudocar- dinals and one short, truncated lateral; beak cavities deep, not compressed ; nacre bluish-white in the young shell, having a reddish-salmon tint in the cavity of the older shell; adductor scars shallow; dorsal scars apparently wanting. The female shell is quite narrow in front and has a wide, rounded, quite prominent marsupial swelling, which reaches forward to the 170 LAMPSILIS middle of the shell, and a very blunt, posterior point about on the median line. ‘The male shell is not so full at the post-basal part, and ends in a blunt point behind midway up from the base. Length (male) 53, height 35, diam. 26 mm. Length (female) 30, height 22, diam. 13 mm. Type locality, Rio Salado, New Leon, Mexico. Bayou Teche, Louisiana ? Unio saladoensis Lea, Pr. Ac. N. Sci. Phila., IV, 1860, p. 305; ji. Ac. No Sci. Phila., TV, 1860, p: 376, plaxv, fie-105;; Obs., VIII, 1860, p. 52, pl. Lxv, fig. 195. Margaron (Unio) saladoensis Lea, Syn., 1870, p. 62. Lampsilis saladoensis SIMPSON, Syn., 1900, p. 569. At the time I wrote the Synopsis I had not seen an example of this shell. Since then I have examined a small female shell from Mexico, which agrees well with Dr. Lea’s description of the above species, and another much larger, which is a male and no doubt belongs to the same species, which is said to come from Bayou Teche, Louisiana. The species evidently belongs in the subgenus Proptera but differs to quite a marked degree from all others. It is shorter, and more inflated than any other species in the subgenus, and is remarkable for its peculiar rays and the apparent want of dorsal muscle scars. Group of Lampsilis wmbrosa. Shell solid, inflated, short elliptical, covered with a shining, rather smooth brownish epidermis, which often has microscopic, radiating folds; beak sculpture excessively faint, being the merest hint at a double loop, with the nacre at the anterior end suddenly thickened; that of the male scarcely differing from the female ; hinge teeth well developed ; pseudocardinals strong ; laterals large, straight, and club-shaped; nacre whitish or pur- plish. Animal having the inner gills united to the abdominal sac; branchie large; marsupium occupying the whole outer gills posteriorly, not projecting much below ; palpi large, con- siderably united behind. LAMPSILIS I71 LAMPSILIS UMBROSA (Lea). Shell somewhat obovate, subsolid, subinflated, with rather low beaks, whose sculpture is very feeble; surface nearly smooth, nearly or quite rayless ; epidermis dark brown or black- ish; posterior ridge low, somewhat double, generally having a darker line on the upper ridge; left valve with two subcom- pressed, somewhat ragged pseudocardinals and two remote, curved, club-shaped laterals, the lower the larger; right valve with one pseudocardinal, a vestigial one above it and one club- shaped lateral; beak cavities shallow, with a few pits; muscle scars superficial, the posterior large; nacre white or purplish. Male and female shells much alike, ending behind in a siight biangulation one-third of the way up from the base ; both shells are a little full in the posterior base, that of the female a little more produced. Length go, height 53, diam. 30 mm. Vera Cruz, Mexico. Unio umbrosus Lea, Pr. Ac. N. Sci. Phila., VIII, 1856, p. 95; Jl. Ac. N. Sci. Phila., JII, 1857,"p. 311, pl. xxx, fig. 26; Obs., VI, 1857, p. 31, pl. xxx, fig. 26—Sowexrsy, Conch. Icon., XVI, 1866, pl. xxxi1, fig. 170.—FiscHER and Crossr, Miss. Scie Ete 7. 1h, 1804ep.. 507; Pin LXVIL, igs. b,/1a, 1D. Margaron (Unio) wnbrosus Lea, Syn., 1870, p. 41. Lampsilis umbrosus SIMPSON, Syn., 1900, p. 570. Unio veracrusensis Lea, Pr. Ac. N. Sci. Phila., XII, 1868, p. 150; Ji. Ac. N. Sci. Phila., VI, 1869, p. 320, pl. Lu, fig. 1225 Obs., XU, 1860; p. So, pl. wit, fie. 133. Margaron (Unio) veracrusensis LEA, Dy 1O70) Pp. 45. Unio tampicoensis var. wmbrosus von Martens, Biol. Cent: Amer. Moll., 1900, p. 512, pl. xxxv, figs. 3-50. An abundant species, having a peculiarly rich texture. It is considerable less solid and inflated than berlandieru, but more inflated than tampicoensts. The type of veracruzensis is in the Smithsonian collection, and is undoubtedly a very young umbrosa. 172 LAMPSILIS LAMPSILIS BERLANDIERIL (Lea). Shell somewhat rhomboid, inflated, solid, with full, high beaks, a large ligament and a very low wing; beak sculpture almost wanting; surface with irregular growth lines, nearly smooth, nearly or quite rayless, the young shell pale brownish, adult or old shells dark brown; posterior ridge rather high and rounded ; left valve with two high, ragged pseudocardinals and two short, remote, club-shaped laterals; right valve with two pseudocardinals, the upper smaller, and one lateral; beak cav- ities full and deep, with a few scars under the shelf of the hinge; anterior muscle scars deep; posterior scars very large in adult shells, suborbicular; nacre purplish, much thicker in front. In both male and female shells the rounded posterior point is below the median line, the female shell is but very lit- tle fuller on the posterior base than that of the male. Length 105, height 75, diam. 50 mm. Northeastern Mexico; southwestern Texas. Type locality, Matamoras and Tamaulipas, Mexico ; Colora- do River, Texas. Unio berlandierti Lea, Pr. Ac. N. Sci. Phila., I, 1857, p. 101; Jl. Ac. N. Sci. Phila., IV, 1860, p. 369, pl. Lxv, fig. 194; Obs., VIII, 1860, p. 51, pl. Lxv, fig. 194.—Rerve, Conch. Icon. XVI, 1865, pl. xxi, fig. 108. Margaron (Unio) berlandierii Lea, Syn., 1870, p. 36. Lampsilis berlandieri Stmpson, Syn., 1900, p. 570. A larger, solider, more inflated and more rhomboid shell than umbrosa, having higher, fuller beaks and larger, deeper beak cavities. LAMPSILIS TAMPICOENSIS (Lea). Shell subrhomboid, scarcely inflated, subsolid, with moder- ately full beaks, which have exceedingly faint sculpture, with a small, rounded posterior ridge; surface rather smooth, with a glossy, dark chestnut or blackish epidermis; left valve with two subcompressed pseudocardinals and two remote slightly curved laterals; right valve with two pseudocardinals, the lower the higher, and one lateral ; beak cavities deep, compress- LAMPSILIS 173 ed, with a few pits under the hinder pseudocardinal, muscle scars superficial, the hinder large; nacre purple, iridescent, and thinner behind. The male and female shells are very much alike and they end in a faint, wide biangulation a short dis- tance above the base. Length 80, height 60, diam. 28 mm. Another, length 120, height 76, diam. 50 mm. Northeastern Mexico; southeastern Texas; Honduras. Unio tampicoensis Lva, Tr. Am. Phil. Soc., VI, 1838, p. 24, pl. vir, fig. 18; Obs., IT, 1838, p. 24, pl. vu, fig. 18.—CHENU, Ill. Conch., 1858, pl. xx1, figs. 5, 5a, 5b.—?Kuster, Conch. Cab. Unio., 1862, p. 275, pl. xc, fig. 1—?Sowxrrsy, Conch. Icon., XVI, 1867, pl. Lvl, fig. 291—von Martens, Biol. Cent. Amer., Moll., tg00, p. 511, pl. xxi, figs. 1, Ia, 1b. Margarita (Unio) tampicoensis Lea, Syn., 1836, p. 22; 1838, p18: Margaron (Unio) tampicoensis Lea, Syn., 1852, p. 26; 1870. p. 41. Lampsilis tampecoensis SIMPSON, Syn., 1900, p. 570. Unio heermanniti Lea, Pr. Ac. N. Sci. Phila., XIII, 1861, p. 202; jl Ae. N. Sei. Phila: V, 1862, p: 194; pl. xxv1, fig. 263; Obs., IX, 1863, p. 16, pl. xxv1, fig. 263.—? SoweRsy, Conch. Icon., XVI, 1868, pl. LXxx111, fig. 441. Margaron (Unio) heermannu Lea, Syn., 1870, p. 28. Close to berlandierii but less inflated and solid, with lower beaks, generally darker within and without. But there are in- termediate shells that are hard to place. It attains larger di- mensions than those given above. The female shell of tam- ficoensis is a little fuller behind the center of the base than the male is. LAMPSILIS TECOMATENSIS (Leay. Shell elliptical, somewhat inflated, solid, with moderate, faintly biangulate posterior ridges, with full, rather high beaks, whose sculpture is not known; epidermis thick, blackish, smooth and shining on the middle of the disk, a little rough- ened around the border and especially on the posterior slope, 174 LAMPSILIS dark reddish-brown or blackish, becoming olive-colored on the umbonal region; left valve with two strong, subtriangular pseudocardinals, which the rough above, and two somewhat remote laterals, the upper smaller; right valve with three pseudocardinals, the central one large and triangular, the other two faint; beak cavities moderate, with a row of dorsal scars under the hinge; anterior cicatrices well impressed ; pos- terior cicatrices large, distinct; nacre dark, lurid purple, with a coppery iridescence behind, thicker in front. The only spec- imen I have seen, the type, is probably a male and is very slight- ly rhomboid, being feebly and widely biangulate behind near the base; basal line rounded. Length go, height 60, diam. 40 mm. Rio Cosamaloapam, Chacotianguis; Tecomate River, Mex- ico. Unio tecomatensis Lea, Pr. Am. Phil. Soc., II, 1841, p. 30; Tr. Am. Phil. ‘Soc. Vly 1842) p.234, plexi he 48 | Ons. TIT, 1842, p. 72, pl. xxr, fig. 48.—CuHeENu, Ill. Conch., 1858. pl. xxx1, figs. 6. 6a, 6b—Fiscner and Crosse, Miss. Sci., Pt. 7, II, 1864, p. 580, pl. uxv; fis. 63 Uxvi, 1as.454a: Margaron (Unio) tecomatensis Lea, Syn., 1852, p. 27; 1870, p- 50. Lampsilis tecomatensis SIMPSON, Syn., 1900, p. 571. This is not so rhomboid a shell as L. berlandierti, nor so much inflated; its beaks are lower, and it has a darker epi- dermis and nacre. It is shorter, more inflated, rather solider than tampicoensis, and has a darker nacre. LAMPSILIS LiVIDA Simpson. Shell elongate, somewhat obovate, rather thin; anterior end compressed, ridge striated; posterior end subtruncated above, concentrically finely ridged; beaks quite full and high, placed in front of the middle; epidermis smooth, livid olive, much lighter on the beaks. The specimen figured in the Concholo- gia is probably a female and has a slight, elongated, rounded swelling along the posterior base; it is faintly biangulate be- LAMPSILIS i75 hind at the end of the somewhat double posterior ridge, the extreme posterior point being just below the median line. Length 110, height 62 mm.; diameter not given. Rio. Usumasinto, Portugal, according to Reeve, who no doubt intended this for Rio Usumacinta, Mexico, and Guate- mala. Unio testudineus ReEve, Conch. Icon., XVI, 1865, pl. xx, fig. 101. Unio explicatus Fischer and Crosst, Miss. Sci., Pt. 7, II 1894, p. 594. Lampsilis lividus Stmpson, Syn., 1900, p. 571. ) Very close to L. explicata, Morelet, and believed to be that species by Fischer and Crosse in the Mission Scientifique. It is somewhat obovate, while the exfplicata holds the same width throughout; it has much fuller, higher beaks, and Sowerby states that it is a thin shell, while specimens of explicata of the size of Sowerby’s figure are rather solid. If his specimen is a female, as I suspect it is, the marsupial swelling is less de- veloped and quite different from that of erplicata. I have recently seen a left valve of a shell sent by Dr. von Ihering from the Rio Lacantun, Chiapas, Mexico, which agrees well with Reeve’s figure of U. testudineus and is more inflated and less high than specimens of Lampsilis explicata in the National Museum collection. This valve measures 82 millimeters in length, 43 in height, and shows the shell to be 28 millimeters in diameter. I have no doubt but that it is the testudineus of Reeve and that it differs from the 1. erplicata of Morelet. LAMPSILIS EXPLICATA (Morelet). Shell large, subrhomboid or long elliptical, rather solid, sub- inflated, with a large brown ligament; beaks moderately full and high, their sculpture scarcely developed: posterior ridge moderate, sometimes rounded, sometimes a little angular ; sur- face with concentric growth lines, which are strong anteriorly but almost fade out in the middle of the shell; color smoky- brown, paler in young shells, darker in old specimens, the umbonal region lighter and livid; left valve with two small, 176 LAMPSILIS compressed pseudocardinals, the anterior the higher, and two remote laterals; right valve with one pseudocardinal, a ves- tigial one above it, and one granular lateral; beak cavities deep with an irregular, double row of dorsal pits; anterior scars moderately impressed; posterior scars shallow, large; nacre white or pale purplish, thicker in front. ‘The male shell is somewhat rhomboid, the posterior termination being widely rounded and below the median line; the female shell has a small marsupial swelling at some distance in front of the pos- terior end; the posterior termination is nearly midway up from the base. Length 112, height 70, diam. 45 mm. Central America; Tabasco, Mexico. Unio explicatus More.et, Test. Noviss, Pt. 1, 1849, p. 28.— FiscHER and Crosse, Miss. Sci., Pt. 7, II, 1894, p. 594, pl. Ex fos ore Lampsilis explicatus SIMPSON, Syn., 1900, p. 571. Margaron (Umno) semigranosus LEA, Syn., 1870, p. 34. A fine series of this species has been lately received by the National Museum from Tabasco, Mexico, collected by Messrs. Nelson and Goldman. I,AMPSILIS SAPPERI von [hering. “This is the shell mentioned by Simpson in his Catalogue, p. 571, n. 4, as a doubtful variety of L. explicatus. The shell is more elongate, with the ventral margins sinuate and the an- terior extremity lower and somewhat obliquely truncate on the inferior part of the anterior margins. The pseudocardinals are very stout, one in the right, two in the left valve. This differs remarkably from L. explicatus as figured by Crosse and Fischer, pl. 61, fig. 1, of the Moll. Mex., having the pseudocar- dinals elevated, compressed, lamelliform. I believe the L. sap- peri more allied to L. umbrosus Lea than-to e.xplicatus, being. however, of a more elongate form with produced posterior extremity and larger size. The type example has a length of 64 mm., breadth of 114 mm., diam. of 38 mm. The epidermis is dark brown, blackish, the nacre white. The posterior slope LAMPSILIS C77 has two obtuse, somewhat indistinct diverging lines. The spe- cies is from the Chixoy River, in Guatemala, and dedicated to Dr. Carl Sapper, who has collected, in scientific expeditions in Central America and Mexico, many interesting Unionide, for which I am much indebted to him.” (von Ihering.) Lampsilis explicatus, Stmpson, Syn., 1900, p. 571, n. 4. Lampsilis sapperi von TiteRtnc, Naut., XV, 1901, p. so. LAMPSILIS FIMBRIATA Frierson. “Shell large, elliptical, thin and compressed. Dorsal line in- curved in front of the beaks. Anterior margin somewhat ob- truding, obtusely pointed or sharply elliptically curved. Basal margin nearly straight, occasionally slightly arcuated. Poste- rior margin broadly, roundly biangular. Beaks low and with- out sculpture. Posterior ridge elevated, rounded and obsolete. The greatest diameter of the shell being about the center of the ridge. Sides flattened and generally somewhat constricted ' in the middle. Behind the posterior ridge, down the siphonal area extends a raised line, enclosing a triangular area, (having its apex at the beak), which is sculptured with small pustules arranged in upturned lines. Epidermis yellow, horn-color, sometimes obsoletely rayed on the posterior slope. ‘The shell would seem to be nearly smooth, but in all the specimens seen there are numerous irregular, radial, pit-like impressions and concentric striz and shallow sulci. The radial impressions, or pits, extend through the shell and are visible inside and out. Hinge ligament stout and rather long. Muscle scars well marked, separate in front and confluent behind. Teeth stout, double in the left and single in the right valve. Beak cavities shallow, with a row of muscle scars running downward, for- ward and onto the base of the cardinal tooth. Nacre white, flesh-color or dark purple, very irregularly laid on and very thin. Except in.old shells, the prismatic structure extends far beyond the nacre and the epidermal layer, in turn, extends still further. Length 80, height 47, diam. 25 mm.” (Frierson.) Type locality, Valles River, Mexico. 178 LAMPSILIS Lampsilis fmbriata Frierson, Naut. XXI, 1907, p. 86, pl. x11, two upper figures and lower left-hand figure. Paraptera (?) fimbriata OrtMANN, Ann. Car. Mus., VIII, IOL2, p.°432. Lampsilis salinasensis Simpson, Pr. U. S. Nat. Mus. XXXV, 1908, Po IS, plo Kxx, he. 3. “The shell is not related very closely to any species that I know of. In fact I am undetermined whether to place it in Lampsilis or in Nephronaias. In the absence of any data re- garding the animal, it is provisionally placed in Lampsilis. The prismatic layer is 3-16 inch wide at the edge in some cases. This peculiarity accounts for the pitting, and numerous irreg- ular sulcations being, it is evident, not normal, but the result of numerous accidents, which befall the extremely delicate edge of the shell. The two upper figures represent the type speci- men; the lower left-hand figure is a young shell.” LAMPSILIS ALIENIGENA (Crosse and Fischer). Shell evenly long elliptical, subinflated, solid, with a very low, somewhat double posterior ridge, which ends behind in a slight biangulation at the median line; with a very imperfectly developed wing ; ligament large; epidermis brilliant brown-olive with very feeble rays; beaks moderately full, apparently not high; hinge rather delicate; left valve with two compressed, ragged pseudocardinals and two long laterals; right valve with two pseudocardinals, the upper smaller and one long lateral ; muscle impressions shallow ; nacre rose-color. Length 82, height 51, diam. 30 mm. Goatzalcoalcos, Vera Cruz, Mexico. Unio alienigenus Crosse and Fiscuer, Jl. de Conch., XLI, 1803, p. 294.—F1scHER and Crosse, Miss. Sci., II, 1894, p. 590. pl. Lxv, figs. 5, 5a; pl. Lxvi, fig. 3—von MARTENS, Biol. Cent. Am. Moll., 1900, p. 513, pl. xxxv, fig. 2-2a. Lampsilis alicnigenus SIMPSON, Syn., 1900, p. 572. I have only seen a young male specimen of what I refer to this species with doubt, and this is considerably decorticated. LAMPSILIS 179 The figures in the Mission Scientifique represent adult males probably, which are scarcely produced at all on the posterior base, and have an evenly rounded posterior outline save for a slight biangulation midway up from the base. It is a more evenly elliptical shell than wmbrosa, but not so elongated as livida. von Martens figures a smaller female shell, which he refers to this species and this has a moderate marsupial swell- ing. Group of Lampsilis metallica. Shell rather small, obovate-rhomboid, inflated, much narrow- ed and rounded in front, the form approaching that of a Modiolus ; epidermis a rich coppery bronze, shining ; beak sculp- ture consisting of two faint, rounded loops, the bars of which are inclined to be nodulous; pseudocardinals compressed, not well developed, and sometimes more or less broken into den- ticles; laterals distinct; pits in the beak cavity numerous and’ very irregular; nacre dark, coppery to purple, with metallic tints, iridescent behind. Animal unknown. LAMPSILIS METALLICA (Say). Shell small for the group, scarcely inflated, thin but strong, subrhomboidal, with a very faint post-dorsal wing, the hinder part of the posterior slope obliquely truncated; beaks low, rather full, with a few broken, doubly-looped ridges, the loops rounded below; posterior ridge high, very wide and rounded; surface nearly smooth, shining, metallic copper-colored ; left valve with two subcompressed pseudocardinals and two deli- cate, remote laterals; right valve with one pseudocardinal, a vestige of another above it and one lateral; beak cavities shal- low, containing a few indistinct pit marks; nacre rich copper- colored, iridescent and thinner behind. I have seen only what I presume to be male shells of this somewhat rare species and these are somewhat rhomboid, being truncated on the posterior slope, the posterior end widely rounded below. ‘The base line is very slightly curved and the anterior end is rounded and narrowed. T,ength 48, height 28, diam. 17 mm. 180 LAMPSILIS Mexico; no special locality is recorded with certainty. The habitat, ake Chalco in the State of Mexico, given by Say, is very much doubted by Fischer and Crosse. Unio metallicus Say, N. Harm. Disseminator (newspaper form), January 15, 1831,; Am. Conch., VI, 1834. Lampsilis metallicus SIMPSON, Syn., 1900, p. 572. Unio cuprinus Lea, Tr. Am. Phila. Soc., IV, 1831, p. 94, pl. x1, fig. 24; Obs., 1, 1834, pl. xu, fig. 24.—HAaN.ey, Biv. Shells, 1843, p. 208, pl. xxu, fig. 7—CueENu, Ill. Conch., 1858, pl. x1, figs. 3, 3a, 3b—Sowerrpy, Conch. Icon., XVI, 1868, pl. LXxvI, fig. 336. Margarita (Unio) cuprinus Lea, Syn., 1836, p. 39; 1838, p. 25. Margaron (Unio) cuprinus Lea, Syn., 1852, p. 38; 1870, p. 61. Unio ereus Reeve, Conch. Icon., XVI, 1856, pl. xxx, fig. 160. A beautiful little species with a shining, coppery epidermis and a rich metallic nacre, which cannot be mistaken for any other. Var. ganina Pilsbry. “The shell resembles L.. metallica (Say) (Unio cuprinus Lea) in general appearance, but is constantly smaller, more com- pressed and more reniform. Near the beaks there are green rays on a pale ground, the rest of the valve being brownish- black. Length 47, height 25, diam. 13% mm. Length 471%, height 26%, diam. 16 mm. Length 30, height 21, diam. 13 mm.” (Pilsbry.) Type locality, Ganina River, three miles southwest of San Dieguito, Mexico. Lampsilis metallica ganina Pirspry, Pr. Ac. N. Sei. Phila., 1909, p. 539, pl. xxvui, fig. 6. Var. subventralis (von Martens). “Ventral margin distinctly convex. Vertices in 2/9 long. Length 55, alt. vert. 20, ale 29, diam. 18 mm. Type locality, Southeast Mexico: Tabasco.” (von Martens.) Unio cuprinus subventralis von Martens, Biol. Cent. Amer. Moll., 1900, p. 506, pl. xxxvI, figs. I, Ia, 1b. LAMPSILIS 181 Group of Lampsilis gracilis. Shell large, thin, elliptical or slightly obovate, with a high posterior and an anterior wing, not greatly inflated; beaks low; epidermis rather smooth, often feebly rayed, dull colored, but usually glossy; hinge line slightly and rather regularly curved ; teeth compressed, pseudocardinals but feebly and often imperfectly developed ; nacre purplish-tinted, dull. Shell of the male and female nearly alike, the latter scarcely swollen at post- basal region. Animal having the mantle greatly thickened at the posterior end, and double and thickened at the post-base, where it is often crenulate or toothed on its inner border, and has the outer developed into a flap; inner gills united to the abdominal sac throughout ; marsupium enormous, composed of a great number of delicate, semiradiating ovisacs, projecting far below the inner gills in a semicircle. LAMPSILIS GRACILIS (Barnes). Shell large, thin, obovate, subcompressed to subinflated, with generally low compressed beaks having very feeble sculpture, which shows a tendency to be doubly looped; posterior ridge almost wanting, there being two or sometimes three radial raised lines on the posterior slope; there is a moderately de- veloped posterior wing, which is broken away in adult speci- mens showing the long ligament, and in front of the hinge the young shell is angular; surface rather smooth, with faint, ir- regular growth lines, greenish-yellow or pale smoky-brownish, sometimes feebly raved, often rayless, the posterior slope dark green and generally rayed; left valve with two feeble, com- pressed pseudocardinals and two remote, often imperfect, lat- erals; right valve with one pseudocardinal and one truncate lateral; beak cavities shallow, showing a row of ill-developed muscle scars running in the direction of the retractor muscle scar; adductor scars large, faint, the anterior irregular; nacre faint purplish and bluish. Generally the male and female are much alike, the former is sometimes a little rhomboid and again it ends in a wide, rounded point about on the median 182 LAMPSILIS line. The female shell is a little fuller and more rounded on the post-basal region, and sometimes has a_ well-developed marsupial swelling. Length 138, height 80, diam. 37 mm. Entire Mississippi River drainage; St. Lawrence system; Red River of the North; Hudson River; eastern Texas. Type locality, Wisconsin River and “the lakes.” Unio gracilis BARNES, Am. Jl. Sci., VI, 1823, p. 274.—DeEs- HAYES, T'r. Element. Conch., 1839, p. 18, pl. xxx, figs. 2, 3.— Hantey, Biv. Shells, 1843, p. 174, pl. xx, fig. 37.—DeEs- HAYES, I'r. Elem., IT, 1853, p. 217, pl. xxx, figs. 2, 3.—Sow- ERBY, Conch. Icon., XVI, 1866, pl. xxxrx, fig. 215. Mya gracilis Exton, Zool. Text-Book, 1826, p. 222. Symphynota gracilis Lea, Tr. Am. Phil. Soc., IIT, 1830, p. 452; Obs., I, 1834, p. 66. Margarita (Unio) gracilis Lea, Syn., 1836, p. 11; 1838, p. 13. Metaptera gracilis Stimpson, Shells of N. Eng., 1851, p. 14. Margaron (Unio) gracilis Lea, Syn., 1852, p. 19; 1870, p. 28. ? Anodon gracilis SowrRBy, Sowerby’s Genera, No. XVII, 1823, fig. Lampsilis gracilis BAKER, Moll. Chicago, Pt. I, 1898, p. 99, pl. X1x, fig. I—SIMPSON, Syn., 1900, p. 573. Paraptera gracilis ORrMANN, Ann. Car. Mus., VIII, 1912, p. 331. Unio fragilis Swatnson, Zool. Ill., 1st ser., III, pl. cLxx1, 1823.—Conrab, Monog., VI, 1836, p. 55, pl. xxx.—KUuSTER, Conch. Cab. Unio, 1852, p. 19, pl. 111, fig: T. Symphynota fragilis Ferussac, Guer. Mag., 1835, p. 25. Metaptera fragilis Conrap, Pr.. Ac. N. Sci. Phila., VI, 1853, p. 260. Unio fragilis var. gracilis Paste, Conch. Sam., III, 1890, p. 153- Mya plana Eaton, Zool. Text-Book, 1826, p. 221. Unio planus Conran, New F. W. Shells, 1834, p. 71. Unio (Nita) atrata Swainson, Zool. IIll., 1841, pl. CLXX1. Unio atratus Hantry, Test. Moll., 1842, p. 199; Biv. Shells, 1843, p. 199, pl. xx1, fig. 29. LAMPSILIS 183 Thinner and more evenly elliptical, with a less developed marsupial swelling than alata, and it has much lighter colored nacre. It is more elongated, is duller colored and has a less developed wing than levissima. Ortmann, (Mem. Car. Mus., IV, I9II, p. 334), has made this species the type of a new genus, Paraptera, based on the shape of the glochidia, which are of the usual Lampsiline type, with- out spines and very small. I,AMPSILIS LASVISSIMA (Lea). Shell, without the wings, nearly evenly elliptical, a little wider behind with a decided posterior and anterior basal gap, thin, subcompressed, strongly alate, having a very high, trian- gular posterior wing that is often flexed at the top, and a smaller anterior wing ; beaks subcompressed, not high, with a few nodulous, broken, slightly-looped ridges; surface with nu- merous irregular growth lines and sculptured in fine specimens _ with delicate radiating liree, smoky-olive, lighter at the beaks, the rest bands dark, brilliantly polished ; left valve with one or two feeble, compressed pseudocardinals and two remote, deli- cate laterals; right valve with one pseudocardinal, sometimes a faint one above it, and a high, truncated lateral; beak cavities shallow, with an irregular row of shallow scars ; adductor scars large and shallow ; nacre purplish. The male and female shells are so near alike that it is often difficult to separate them. The male shell is generally slightly rhomboid behind and the female is a very little fuller along the base than the male. Length 120, height without measuring the wing 76, diam. 37 mm. The wing when well preserved in adult shells is about 25 mm. in height. Mississippi drainage generally; eastern Texas; southern Michigan ; western New York. Type locality, Ohio. Symphynota levissima Lua, Tr. Am. Phil, Soc, 11}, 1830, p- 444, pl. x1, fig. 23 ; Obs. I, 1834, p. 58, pl. x11, fig. 23. Unio levissima DesHayeEs, An. sans Vert., 2d ed., ViEwSe5nip- 55°. 184 LAMPSILIS Unio levissimus Conrap, New F. W. Shells, 1834, p. 70.— Hantey, Biv. Shells, 1843, p. 174, pl. xx1, fig. 41.—SoweEr- By, Conch. Icon., XVI, 1866, pl. xLv1, fig. 250. Margarita (Unio) levissimus Lea, Syn., 1836, p. 11; 1838. pols: Margaron (Unio) levissimus LA, Syn., 1852, p. 19; 1870, p. 28. Lampsilis levissimus S1MPSON, Syn., 1900, p. 574. Proptera levissima OrtTMANN, Ann. Car. Mus., VIII, 1912, p. 324. Unio ohioensis SAy, Am. Conch., VI, 1834.—Kuster, Conch. Cab., 1866, p. 20, pl. LxIx, fig. 5. Symphynota ohioensis Frrussac, Guer. Mag., 1835, p. 25. Metaptera ohiensis Conrap, Pr. Ac. N. Sci. Phila., VI., 1853, p. 260. Unio discoideus Sowrrry, Conch. Icon., XVI, 1866, pl. Lim, he 27 5 Generally a little less elongated and more brilliant than L. gracilis, and it has feeble radial sculpture and a higher wing. Its nacre is usually darker than that of gracilis. LAMPSILIS INFLATA (Lea). Shell somewhat trapezoidal, being truncate on the posterior slope and narrowed in front, thin, subinflated, having its great- est diameter just behind the center; dorsal wing probably high in young shells ; posterior ridge high and widely rounded ; beaks low and compressed, their sculpture not seen; epidermis green- ish-olive to dark brownish, scarcely shining, nearly or quite rayless; in young shells there is often one or two faint, wide, dark rays on the posterior slope; left valve with a feebly de- veloped, elongated pseudocardinal and two short, remote lat- erals; right valve with one faint, elongated pseudocardinal and one high, short, truncated lateral; beak cavities shallow, with a row of irregular, large scars; adductor scars shallow, the an- terior ones large; nacre rich purple, iridescent behind. There seems to be but little difference between shells of the male and female. LAMPSILIS 185 Length 105, height from broken point of wing 78, without the wing 72, diam. 38 mm. Alabama and Tombigbee River areas. Type locality, Alabama River. Symphynota inflata Lea, Tr. Am. Phila. Soc, LV, 163%, p--09;. pl. x1v, fig. 28; Obs., I, 1834, p. 109, pl. xiv, fig. 28. Metaptera inflata Conran, Pr. Ac. N. Sci. Phila., VI, 1853, P. 260. Margarita (Unio) inflatus Lea, Syn., 1836, p. 11; 1838, p. 13. Unio inflatus Conrav, Monog., VII, 1836, p. 57, pl. XXX1I.— Hantry, Biv. Shells, 1843, p. 174, pl. xx1, fig. 45.—KustTer, Conch. Cab. Unio, 1852, p. 17, pl. 1, fig. 1—Sowersy, Conch. Icon., XVI, 1866, pl. xv, fig. 246. Margaron (Unio) inflatus Lua, Syn., 1852, P. 28; 1870, p. 28. Unio alabamensis Conrap, New F. W. Shells, 1834, p. 67. Lampsilis alabamensis SIMPSON, Syn., 1900, Pp. 574- Most nearly related to L. lezissima, but it is not evenly elliptical and it has a much higher posterior ridge than that species. It has a decided anterior basal and posterior gape, the latter in the specimen above measured being 7 millimeters across. Lea originally described this species as Symphynota inflata, so that in Lampsilis his name is entitled to precedence, not- withstanding Barnes’ Unio inflatus described in 1823. Group of Lampsilis amphichena. Shell rather thin, elongate, elliptical, rounded before, pointed behind, compressed, with a smooth, shining, black, rayless epi- dermis; beaks not prominent, their sculpture unknown ; there is a conspicuous gape at the anterior base, and another very dis- tinctly outlined at the upper part of the posterior end like that of Schizotherus; hinge line slightly curved; pseudocardinals imperfect ; laterals compressed ; nacre purplish; female shell inflated at posterior base. 186 LAMPSILIS Animal with large, elliptical palpi; mantle slightly thickened at the edge; anal opening widely separated from the superanal, the latter large; foot large, hatchet-shaped. Several animals were examined, but all were so much decayed that most of the characters could not be made out. LAMPSILIS AMPHICH AINA Frierson. Shell large, long elliptical, subinflated, subsolid, with moder- ately full, but not high, beaks, whose sculpture has not been seen; with a long, narrow gape on the anterior base and a most decided one behind just above the posterior point; posterior ridge full, rounded; surface with irregular growth marks; epidermis dark brown to jet black, smooth and shining on the middle of the disk, somewhat roughened and lamellar on the rest of the shell, especially on the posterior slope; left valve with one rather feeble, subcompressed pseudocardinal and a vestigial second one in front of and below it, with two short, very remote laterals; right valve with one pseudocardinal, sometimes with a smaller one above it, and a remote lateral, whose inner edge is curved upward; beak cavities shallow, with an irregular row of large muscle scars running down towards the anterior base; anterior scars large, shallow ; posterior scars small, somewhat elongated; pallial line wide, with a distinct sinus behind; nacre bluish and purplish, somewhat clouded. The female shell differs but slightly from that of the male, being a little fuller just behind the middle of the base and hav- ing the blunt posterior point a trifle higher. Length 120, height 70, diam. 45 mm. The above measure- ments are from a large male shell. Type locality, Saline River, Texas. Unio (Lampsilis) amphichenus Frierson, Nautilus, XI, 1808, Pent, pl. i; Lampsilis amphichenus Simpson, Syn., 1900, p. 575. This is really a remarkable species, the great and distinct posterior gape resembling that of a Schizotherus nuttalli. In the specimen, whose measure is given above, it is about 10 millimeters wide. ‘The anterior basal gap is narrower but ¢x- LAMPSILIS 187 tends to near the extreme posterior base of the shell, becoming narrower behind, and between it and the posterior opening the two valves touch only for a very short distance. Group of Lampsilis simpsont. Shell long, obovate, gaping in front and behind, rounded at each end’; epidermis dull, rayed when young, dark when adult ; teeth very niuch reduced; nacre bluish or purplish. Animal unknown. LAMPSILIS SIMPSONI Ferriss. Shell subsolid, elongated, slightly obovate, narrowed in front and rather evenly rounded at both ends, somewhat inflated, having the greatest diameter in the middle and gradually taper- ing each way to the ends, feebly gaping at the anterior base and at the posterior end; beaks rather low but distinct, their sculpture consisting of ill-defined, irregular, subnodulous cor- rugations ; epidermis in the young projecting beyond the shell all around, showing the uneven growth lines ; color tawny, with green rays and coppery beaks in the young, brownish or black- ish in the adult; posterior ridge well marked in the earlier stages of growth; hinge line evenly curved; pseudocardinals reduced to mere stumpy vestiges; there are two feeble remote laterals in the left valve and one in the right ; epidermal matter folded in along the hinge line; anterior cicatrices rather deep, irregular ; posterior cicatrices shallow ; nacre shaded violet, blu- ish and coppery, iridescent behind. I cannot tell whether the specimen figured is a male or female. Length 95, height 50, diam. 32 mm. Type locality, Spring River, Hardy, Arkansas. Lampsilis simpsoni Ferriss, Nautilus, XIV, 1900, p. 38, fig. This is perhaps most closely related to 1. leptodon and am- phichena, though it resembles to some extent 1. gracilis. Its teeth are much more feebly developed than those of the latter and it is a longer shell. The young are more like those of Jeptodon, but the mature shell is very different from that. 188 LAMPSIILIS Group of Lampsilis leptodon. Shell rather thin, elongate, elliptical, compressed, decidedly pointed behind, the point raised above the center of the shell: beaks low, their sculpture very feeble; there is a conspicuous post-dorsal wing in young shells, and sometimes vestiges of an anterior wing; young shell rather dull and faintly rayed; there is a decided anterior basal and posterior gape; hinge teeth very imperfect: pseudocardinals often alniost wanting, even in young shells; laterals faint, sometimes wanting in the adult shell; nacre coppery to purplish; female shell not inflated at post-base. Animal having the branchiz large, very thin, light brown, free nearly the whole length of the abdominal sac ; palpi large, thin, nearly semicircular ; mantle thin, with a wide crenulate border; marsupium projecting slightly below the in- ner gills. ILAMPSILIS LEPTODON (Rafinesque). Shell irregularly long ovate, the dorsal line being generally more nearly straight than the basal line, very inequilateral, thin to subsolid, rather compressed, with a low, narrowly rounded posterior ridge, slightly winged behind when young, the wing mostly disappearing in adult shells, gaping at the anterior base and behind; beaks low, rather compressed, their sculpture con- sisting of a few very faint, doubly-looped ridges; surface cov- ered with wide, very uneven, often sulcate, growth lines, green- ish, olive-green. or in old shells brownish, with wide, feeble green rays; epidermis not shining; there is a very feeble, low tubercle under or in front of the beaks in each valve, but it is sometimes wholly wanting: left valve with the faintest vestige of one or two remote laterals ; right valve with a stronger single lateral; beak cavities shallow with a row of irregular, large dorsal scars; anterior adductors long, vertical; posterior ad- ductors Jarge; nacre purple, bluish or salmon-color, often clouded. The male and female differ but little; those of the latter have a slightly fuller base, and the rather sharp posterior point is a little higher than in that of the male. Length 117, height 60, diam. 28 mm. LAMPSILIS 189 Upper Mississippi River drainage, south to the Tennessee River; Buffalo, New York; southern Michigan; Souris River, Manitoba. Type locality, lower Ohio River. Unio (Leptodea) leptodon RaFinesqur, Ann. Gen. Sci. Phys. Brix, V,.1O20; p..205, pl. EXKX, figs. 5-7: Unio leptodon Say, Am. Conch., VI, 1834.— Conran, Monog., VII, 1836, p. 58, pl. xxxu1.— CHENU, Bib. Conch., Ist ser., III, 1845, p. 12, pl. 1, figs. 5-7.—Kusrsr, Conch. Cab. Unio, 1861, p. 197, pl. LxIv, figs. 1, 2— Sowerby, Conch. Icon., XVI, 1866, pl. xivuil, fig. 257. Symphynota leptodon FEeRussac, Guer. Mag., 1835, p. 25. Leptodea leptodon Conran, Pr. Ac. N. Sci. Phila, VI, 1853, Pp. 202: Lampsilis leptodon SIMPSON, Syn., 1900, p. 575. Anodon purpurascens Swainson, Zool. Ill., 1st ser., III, pl. Chx, 1823. Unio velum Say, New Harm. Disseminator, II, September 23, 1820, p. 203. Symphynota tenuissima Lea, Tr. Am. Phil. Soc., II, 1829, p. iGo pe eicie. 26 Obs. T1834, p. 67; pl. x1, fig. 27. Margarita (Unio) tenuissimus Lea, Syn., 1836; p. 38; 1838, piL25. Unio tenuissimus Hantery, Biv. Shells, 1843, p. 206, pl. xx, fig. 42— Sowersy, Conch. Icon., XVI, 1866, pl. xutrv, fig. 240. Margaron (Unio) tenuissimus Lea, Syn., 1852, p. 38; 1870, pe Or. A peculiar shell of irregular growth. When viewed from above or below it will be seen that the parting line between the valves is never straight, the shell being more or less twisted to the left or the right or both ways as in the genus Pseudo- spatha. ‘The anterior and posterior openings are very uneven and quite large. The teeth are rudimentary and in some speci- mens almost entirely wanting. 190 LAMPSILIS LAMPSILIS BLATCHLEY! Daniels. “Shell long, elliptical or obovate, compressed, thin, inequilat- eral, slightly gaping behind; beaks low, but little inflated, pointed, with minute, nodulous sculpture; dorsal and_ basal outlines lightly curved; anterior end somewhat narrowed, rounded; posterior end rounded, and lightly and obliquely subtruncate above; surface with singular (regular?) growth lines; epidermis somewhat concentrically wrinkled, projecting beyond the border of the shell, yellow-green with faint green rays; pseudocardinals rudimentary, smooth, subcompressed ; laterals straight, single in the right valve, partly double in the left; nacre brilliant, iridescent, having a somewhat coppery lustre in the cavities, becoming very thin and greenish at the edges. Length 45, height 21, diam. 10 mm. Length 40, height 17, diam. 8.5 mm. Soft parts: Marsupium very large, occupying the posterior two-thirds of the outer gills, each lobe containing apparently about forty narrow ovisacs, the whole rounded and projecting well below the inner gills; inner gills united to the abdominal sac throughout their length; palpi large, elliptical, projecting backward but little; mantle much thickened on the border, its edges being decidedly double wavy and dark colored ; branchial opening rather large, with stout papillz; anal opening small, crenulate; super-anal opening long, closed below; foot rather large.” (Daniels). Type locality, Wabash River, Linn Township, Posey Co., Ind. Also, Hardy, Ark. (?) and Iowa River, Iowa City, Ia.( ?) Lampsilis blatchleyi Danis, Naut., XVI, 1902, p. 13, pl. 0. “The species is closely allied to L. leptodon Raf., particularly in its anatomical characteristics; the shell differs from that species by not having the wing and by the posterior end being rounded and in the full-grown shell being not more than one- half the size.” LAMPSILIS TQI Group of Lampsilis scutulata. Shell rhombic elliptical. compressed, rather thin, with a high posterior and a low anterior wing, with two posterior ridges ; the valves often exhibiting fine radiating plications on the pos- terior part; beaks compressed but very sharp pointed, some- times showing the nepionic shell, almost destitute of sculpture, which, when present, consists of faint indications of two round- ed loops; epidermis rather dull, sometimes indistinctly rayed ; left valve with two pseudocardinals, the anterior a sharp, straight ridge sloping obliquely downward and forward from a point just in front of the beaks, the hinder curiously com- pressed and showing a tendency to break into denticles; right valve with two sharp, ridge-like, sloping pseudocardinals ; lat- erals slender, compressed, straight, or wavy ; nacre bluish-white to pale violet ; dorsal scars few; female shell apparently slightly swollen at the posterior base ; animal unknown. LAMPSILIS scuUTULATA (Morelet). Shell elliptical or elliptic-rhomboid, compressed, thin, green or light olive-green, with a few faint rays, with a low but dis- tinct, somewhat angled posterior ridge, which is sometimes double; surface of the posterior half of the shell with slightly curved, nearly vertical plications ; beaks low, not inflated ; pos- terior wing well developed, angled behind; left valve with two pseudocardinals, the posterior small, and two laterals; right valve with two compressed pseudocardinals and one lateral; nacre bluish on the border, yellowish in the centre of the shell. Both male and female shells are somewhat rhomboid, the for- mer more truncated at the posterior slope. The male shell ends in a blunt point, but a short distance above the base, and the base line is nearly evenly curved ; the female shell is biangulate behind and has a well-developed marsupial swelling at some distance in front of the posterior end. Length 49, height 30, diam. 16 mm. Yucatan. 192 LAMPSILIS Unio scutulatus Morrie, Test. Noviss., I, 1849, p. 30.—Fiscu- ER and Crosse, Miss. Sci., II, 1894, p. 561, pl. i1x, fig. 5; LXVI, fig. 6. Lampsilis scutulatus SIMPSON, Syn., 1900, p. 576. This species, L. planivalvis and L. paludosa, are very closely related and may be mere variations of one thing. This has strong, nearly vertical, ribs on the posterior half of the shell and the male shells are more round on the base than those of either of the other species. L. paludosa has a higher wing than either of the other forms and is shorter than planiwalvis. LAMPSILIS PALUDOSA (Morelet). Shell winged, inequilateral, oval-trapezoidal, compressed, thin, with a greenish-olive epidermis; surface covered with concentric growth lines, slightly radiately sculptured on the umbonal region ; beaks low but sharp, not inflated, with deli- ‘cate, doubly-looped sculpture; posterior ridge well developed and angled; anterior end rounded, angled at the dorsal line; posterior wing considerably developed and angled behind; the shell is decidedly and obliquely truncated posteriorly ; post-basal part sub-biangulate; left valve with two pseudocardinals, the hinder rudimentary, and two lamellar laterals; right valve with two pseudocardinals, the upper the smaller, and one lateral; beak cavities shallow; nacre pale violet-rose; anterior muscle scars superficial ; posterior scars indistinct. The specimen described is probably a male; its basal line is nearly straight and it is considerably rhomboid. Length 57, height 31, diam. 15 mm. Yucatan. Unio paludosus Moret, Test. Noviss., I, 1849, p. 30.—FiscH- ER and Crossr, Miss. Sci., II, 1894, p. 559, pl. L1x, fig. 3. Lampsilis paludosus SIMPSON, Syn., 1900, p. 576. A fine, compressed species with a small, angular wing in front and a larger one behind. It is nearly smooth, the pos- terior slope, however, sometimes has a few plications. It is more inflated and shorter than planivalvis and does not have such high wings as delphinulus. LAMPSILIS 193 LAMPSILIS PILANIVALVIS (Morelet). Shell eomewhat elongated, rhomboid, greatly compressed, with a slight wing in front and a moderately developed one be- hind, with a low, but distinct, angular posterior ridge; beaks low, not inflated, but sharply pointed ; surface with fine growth lines and slightly radially ridged in the umbonal region; epi- dermis brown-olive ; left valve with a thick anterior pseudocar- dinal, and an almost obsolete posterior one, with two lamellar laterals ; right valve with two short pseudocardinals, the upper smaller, and a long, curved lateral; muscle scars shallow ; beak cavities not deep; nacre white. Length 66, height 35, diam. 14 mm. Usumacinta River, Guatemala. Unio planivalzis Moreiet, Test. Noviss., Il, 1851, p. 24.— Fiscurr and Crosss, Miss. Sci., II, 1894, p. 560, pl. LIx, fig. 2. Lampsilis planivalvis StMPSON, Syn., 1900, p. 576. This species is greatly compressed, and has a decided wing in front and behind on the dorsal portion. Like all the other species of the group the general surface of the umbonal region is compressed, but the beaks themselves are elevated into a fine point. The shell figured by Fischer and Crosse is probably that of a male. LAMPSILIS DELPHINULUS (Morelet). Shell with a somewhat triangular outline, thin and much compressed, the body of it elongated subrhomboid, with a near- ly parallel dorsal and ventral lines when freed from the wing, bearing a greatly elevated, somewhat triangular posterior dor- sal wing and a small anterior one, whose dorsal line is parallel with that of the base; beaks low and compressed, with scarcely any sculpture ; posterior ridge low, double or treble, ending be- hind in a blunt, somewhat rounded point about at the median line; surface dull, greenish-yellow or brown, with faint rays 194 LAMPSILIS which often fade out at the border of the shell; the winy 11 fine specimens having a broad, faint, darker ray, whose base lies along the dorsal line; epidermis thin, cloth-like; left valve with an elongate pseudocardinal, sometimes there are vestiges of others, and two straight, delicate laterals; right valve with two lamellar pseudocardinals and one lateral ; beak cavities very shallow with a few pits; muscle scars scarcely discernable ; nacre brilliant, shining with a metallic luster, yellowish or purplish. I have examined a number of shells and in a few there is a slight fullness near the posterior base not seen in others, and these may be females. Length 58, height, with wing, 45, without the wing 26, diam. 10 mm. Guatemala; Monte Cristo, Tabasco, Mexico. Unio delphinulus Morrever, Test. Noviss., I, 1849, p. 31.— Han ey, Biv. Shells, 1856, p. 381, pl. xx, fig. 60.—Sow- ERBY, Conch. Icon., XVI, 1866, pl. xii, fig. 237—FISsCHER and Crosse, Miss. Sci., II, 1894, p. 557, pl. Lx11, figs. 2, 2a, 2b. Margaron (Unio) delphinulus Lea, Syn., 1870, p. 28. Lampsilis delphinulus Stmpson, Syn., 1900, p. 576. A striking and delicate shell. The front line of the great dorsal wing rises at an angle of about 60°; its posterior line forms a perfect ogee from the summit to the posterior point. LAMPSILIS LARGILLIERTI (Philippi). Yucatan. Unio largilherts Pui.ipri, Zeits. fiir Mal., IV, 1847, p. 94— von Martens, Biol. Cent. Amer., Moll., 1900, p. 521. Lampsilis largillierti SIMPSON, Syn., 1900, p. 577. Unfigured and unknown to me. From the description, which is not accessible to me at the present time, I should think that it probably belonged here. von Martens, (1. c.), suggests that it may be the same as paludosa Morelet. LAMPSILIS 195 SPECIES INCERT-E SEDIS. JLAMPSILIS MOCTEZUMENSIS Pilsbry. “The shell is oblong, the dorsal and ventral margins both arched, the former a little more so: altitude decidedly more than half the length, diameter more than one-third the length ; moderately strong, but not thick. The beaks are small and low, near the anterior fourth of the length. In young shells they show one or two low, short undulations, being nearly smooth. Color yellowish-brown. Adult shells hardly showing rays, even by transmitted light, but the young have narrow green rays posteriorly, on a yellow ground, marked with dark concentric streaks. Both ends are rounded. Sculpture of growth-wrin- kles only, weak on the middle of the valve, but rather emphatic anteriorly. The interior is white, the nacre thinner and iri- descent posteriorly. The pseudocardinal teeth are moderately stout, blunt and nearly smooth. In the left valve the posterior cardinal is larger than the anterior. In the right valve the single cardinal is small. The lateral teeth are short and widely separated from the cardinals. The cavity of the beaks are rather deep. Length 68, height 38.5, diam. 24 mm.”’ (Pilsbry.) Type locality, Moctezuma River, State of San Luis Potosi, Mexico. . Lampsilis inoctezumensis Pitspry, Pr. Ac. N. Sci. Phila., 1900, Dese4y plex KV) MOS) T542, 35-4 “This species has some resemblance to spatulatus (Lea). It differs from the related species by wanting corrugations on the posterior slope.” ILAMPSILIS NOvILEONIS Pilsbry. “The shell is oblong, rather compressed, the upper and basal margins slightly and about equally arcuate, anterior end round- ed, posterior end sloping above, truncate and somewhat bian- gular below, beaks at the anterior two-sevenths of the length. The surface is convex, without angle or ridge bounding the posterior slope, not very glossy, smoothish for the greater part, 196 LAMPSILIS but on the posterior slope there is some oblique corrugation in the upper part of the disk. The epidermis is yellow, sparsely marked in the posterior half with narrow green rays. The very low beaks are eroded in the type specimen. ‘The interior is white, thicker anteriorly, very gradually becoming thinner at the posterior end, where opalescent tints are beautifully pro- duced. The cavity of the beak is rather deep. The lateral teeth are short and rather widely separated from the stout car- dinals, which are double and about equally prominent in the left valve. Length 78, height 43.5, diam. 22.5 mm.” (Pilsbry.) Type locality, Casas Viejas River, State of San Luis Potosi, Mexico. Lampsilis novileonts Pirspry, Pr. Ac. N. Sci..Phila., 1909, p. 537; pls KkVInS Hes. 452,27. “With some resemblance to L. moctezwmensis, this species differs by the slight corrugation of the posterior slope and the more compressed form. Some young specimens, (fig. 7), from the type locality, which seem referable to this species, have the whole valves ornamented with wide, green rays. The beaks have a minute area sculptured with about four concentric wrinkles, which are very weakly bilobed. Outside of this sculptured portion the green rays are very distinct, as in allied species. A faint rib or green stripe radiates from the beak in the middle of the posterior slope, which is in part obliquely corrugated. These specimens measure from 17.5 to 36 mm. 9 long. J,AMPSILIS COYENSIS Pilsbry. “The shell is oblong, with beaks at the anterior fourth of its length; slightly wider posteriorly, the posterior end sloping above, biangular below; anterior end rounded; basal outline moderately curved, convex. There is a rather distinct angula- tion from the beak towards the posterior-basal angle, and the indistinct trace of a ridge to the posterior-median angle. The beaks are low, with minute, recurved tips sculptured with a few coarse, double-festooned wrinkles, the connection between the two curves almost interrupted, The sculptured portion is I.AMPSILIS 197 not quite two mm. long. Subsequent growth is marked with growth-lines only, or with a very slight oblique corrugation in places on the posterior slope. ‘The epidermis is smooth, but not glossy, and is shortly and finely lamellose towards the margins. Color, obscure greenish-yellow, indistinctly marked all over with green rays. Near the beaks the rays are verv distinct on a light ground. By transmitted light it is light yel- lowish, very profusely marked with green rays. The interior is white and somewhat thick anteriorly, thin, blue and slightly iridescent in the posterior half. The teeth are moderately strong. Length 36, height 21, diam. 13.5 mm.” (Pilsbry.) Type locality, Coy River, State of San Luis Potosi, Mexico. Lampsilis coyensis Piisspry, Pr. Ac. N. Sci. Phila., 1909, p. 538, pl. xxvut, figs. 3, 4. “This may turn out to be a small, rayed variety of L. novi- leonis, yet specimens from 28 to 36 mm. long have every ap- pearance of adult shells. The cardinal teeth in the left valve are stouter and their crests are more united than in L. novi- leonis. While L. undivaga, coyensis and novileonis are closely related species, they seem, with present material, to be distinct.” LAMPSILIS UNDIVAGA Pilsbry. “The shell is oblong, the altitude about three-fifths of the length, diameter slightly over one-third the length; solid, dull blackish brown, without rays. The anterior end is rounded, posterior end more or less truncate below, sloping steeply above. Surface of the valves with sculpture of distinct growth- lines, and sometimes having a patch of very indistinct vertical corrugations near the posterior ridge on the most convex por- tion. There are also some fine oblique corrugations on the posterior-dorsal slope near the beaks, when not worn oft. Beaks low, between the anterior fifth and sixth of the length: when perfect the tip is acute and sculptured with a series of short folds on the posterior ridge. ‘The interior is fleshy-pur- plish, iridescent posteriorly ; nacre in the anterior half is very thick, posteriorly thin. Cavity of the beaks deep and angular. 198 I.AMPSILIS The pseudocardinal teeth are stout, otherwise formed as in 1. signata; laterals curved. Length 54, height 33, diam. 19 mm. Length 54, height 30, diam. 18 mm. Length 50, height 30, diam. 18 mm.” ( Pilsbry.) Type locality, Valles River, two miles above Mecos, Mexico. Lampsilis undivaga Piissry, Pr. Ac. N. Sci. Phila., 1909, p. 530; Pl XXVI, Hes, 1,2) Bp As VEL giles Be “This species is closely related to L. signata, but the valves are thicker and heavier, the teeth are heavier, and the propor- tions difter. It is apparently related to L. aztecoruwm (Phil.), but that is described as thin, valvulis satis tenuibus,’ whereas in L,. undivaga the valves are quite heavy and strong for a Lampsilis of this size. The nacre is nearly white in a few examples. It abruptly becomes thick, (thin?), in the posterior half of the shell. Young shells are conspicuously rayed with green. One young shell from the Valles River at Valles, (pl. xxvul, fig. 5), seems to belong to this species, though I am not quite sure of the identity. It is 41 mm. long, yellowish, nearly cov- ered with green rays, the nacre is pale purple, with a wide, darker purple margin posteriorly.” I,AMPSILIS SIGNATA Pilsbry. “The shell is oblong with subparallel dorsal and ventral bor- ders, twice as long as wide, the diameter contained about three times in the length. The anterior border is rounded, posterior border truncate below, sloping and more or less convex from the truncation to the posterior end of the hinge. In some spec- imens the posterior truncation is indistinct or that extremity may be rounded. ‘The beaks are low and situated near the anterior fourth of the shell’s length. Adult shells are black- ish, but by transmitted light numerous green rays may be seen, fading out toward the lower border; and when unworn the beaks show a pretty pattern of distinct green rays on a pinkish or creamy ground. The surface has but little gloss ; the cuticle LAMPSILIS 199 is roughened by growth-lines, which near the edge and on the posterior slope often form cuticular laminz; the middle part of the valves is smoother, but marked with one or more small patches of short corrugations, at right angles to the growth- lines, and near the beaks there are some acute, fine; radial wrinkles on the posterior-dorsal slope. The beaks are sculptured with two radial series of short, concentric wrinkles separated by a slight depression. The valves are rather thick in the anterior half, becoming abruptly thinner posteriorly. The nacre is purple, fading in the cavity, or bluish-white, becoming purplish and iridescent posteriorly. The pseudocardinal teeth are stout, the anterior one in the left valve wedge-shaped, a rather broad rugose heel below it, the posterior one lying directly under the beak ; lateral teeth double as usual. The right valve has a stout, rugose pseudocardinal with a fossa and then a very small, compressed laminar tooth above it; lateral tooth single. Length 73, height 37, diam. 23 mm.” (Pilsbry.) Type locality, Valles River, about three miles below Valles, Mexico. Lampsilis signata Pitspry, Pr. Ac. N. Sci. Phila., 1909, p. 536, DlexxKVe hose 5. O ple xxvi, fies. 5, 6: LAMPSILIS SEMIRASA Pilsbry. “The shell is oblong-reniform, the ventral margin being a little concave in the middle or straight, the upper margin strongly arched; the posterior end is wider in female shells, scarcely so in males. The altitude is contained about 134 times in length, diameter about three times in the length. The sur- face is smoothish except for growth-lines, which are strongest near the lower margin and anterior end. Color various shades of brown, with rather indistinct darker or greenish rays, chiefly on the posterior half. The beaks are low, at the anterior fifth of the length. When perfect they have double-looped, concen- tric sculpture. Valves thin, lined with nacre, which is whitish in the cavity and anteriorly, but pink and very iridescent pos- teriorly, (sometimes suffused with pink throughout, darker 200 FRIERSONIA and purplish below the pallial line or sometimes silvery white throughout). Pseudocardinal teeth compressed, rather small ; lateral teeth very short, about one-third the shell’s length. Ligament short. Length 47, height 26, diam. 15 mm.” ( Pilsbry.) Type locality, Ganina River, three miles southwest of San Dieguito, Mexico. Also in the Valles River at and above Mecos, Mexico. Lamplhsis senurasa Pitspry, Pr. Ac. N. Sci. Phila., 1909, p- 534, pl. xxv1, figs. 7, 8. 9. “Some specimens of the type lot are larger, length 55, height 28, diam. 16 mm. There is also some variation in the teeth, which may be more or less stout. L,. semirasa differs from L,. signata and L. undivaga by lack- ing corrugation on the convexity of the valves and on the pos- terior-dorsal slope.” The following are unfigured and unknown: Lampsilis fasciola RAFINESQUE, Ann. Gen. Sci. Brux., V, 1820, Pp. 299. Lampsilis fulgens RAFINESQUE, Cont. Monog., 1831, p. 7. Lampsilis argvratus RAFINESQUE, Cont. Monog., 1831, p. 7. Genus FRIERSONIA Ortmann, 1912. “Shell subelliptical, without distinct posterior ridge. Disk not sculptured. Beak-sculpture of the double-looped pattern, con- sisting of six to eight fine bars, of which the later ones are distinctly double-looped, and the latest are interrupted (uncon- nected) in the middle. Epidermis greenish-yellow, with rather distinct, simple rays. Male and female shells hardly different. Inner lamina of inner gills connected with abdominal sac. Edge of mantle in front of branchial slightly laminate, with fine and distinct crenulations, disappearing gradually in front, but without papilla. A brown streak of pigment along this part of the edge. Marsupium consisting of many ovisacs, occupying the larger posterior section of the outer gill. When FRIERSONIA 201 gravid, the ovisacs swell very little, and they are only slightly compressed in the basal part, which is largely enclosed between the laminz of the gill. The ovisacs reach considerably beyond the edge of the gill, and in this region they are curved back- ward in a peculiar manner, subcylindrical, and tapering towards a point directed backward at the hind end of the marsupium. The marsupium has also a remarkably sharp edge. Placentz not very solid. Glochidia lying all through the placental mass, of medium size, and subovate in shape.” (Ortmann. ) Type Lampsilis iridella P. and F. Friersonia ORTMANN, Ann. Car. Mus., VIII, 1912, p. 318. FRIERSONIA IRIDELLA (Pilsbry and Frierson). “The shell is oblong, wider posteriorly, with the beaks at the anterior two-ninths of the length, anterior end round- ed; posterior part sloping above, subtruncate at the end, compressed below the hinge. Surface glossy, smoothish, obliquely corrugated along the posterior slope, (but sometimes very indistinctly so), and usually having a group of short, im- pressed lines or furrows vertical to the basal margin, near the middle of the disk. Of a dull straw or pale greenish color, profusely marked with green rays, which are usually quite dis- tinct and narrow. The valves are thin, nacre bluish-silvery, very iridescent posteriorly. Cardinal teeth small, a single rather stout one in the right valve, two more compressed and generally subequal teeth in the left valve. Lateral teeth very narrow, double in the left, single in the right valve. Length 49, height 26, diam. 15 mm.” (P. & F.) Type locality, Valles, Mexico. L. iridella, Naut., XXI, 1907, pl. x11, two lower right-hand figs. Lampsilis iridella Pi.spry and Frierson, Naut., XXII, 1908, p. 81. Friersonia iridella ORTMANN, Ann. Car. Mus., VIII, 1912. p. 3210, fig. 19. This species “is related to U. popei and U. medellinus.” 202 PSEUDOSPATHA Genus PSEUDOSPATHA Simpson, 1900. Spatha Smiru, Pr. Zool. Soc. Lond., 1880, p. 350. Burtonia BourcuicNat, Moll. Fluv. Nyanza, 1883, p. 20. Pseudospatha Simpson, Syn., 1900, p. 577.—GERMAIN, Arch. Zool. Exp. et Gen. (5), I, 1909, p. 46. Shell compressed, thin, oblique, inequilateral, with a straight dorsal line, which ends in a small wing in front and behind, rounded and cut away at the anterior base, produced in the post-basal region, gaping in front and behind, slightly twisted on its axis and usually bent posteriorly to the right or left; a low, eften double posterior ridge ends in a biangulate point behind ; beaks compressed, the sculpture faint, irregular, con- centric ridges, which continue over the shell, and at the beaks sometimes become rather sharply pustulous, the glochidium often remaining; epidermis yellowish-brown, sometimes deli- cately rayed; teeth rudimentary, one or more faint, compressed pseudocardinals and a single lateral in each valve ; muscle scars irregular; nacre coppery or purple, often rayed. Animal un- known. Type, Spatha tanganyicensis Smith. The shells of this group bear a striking resemblance to that of Lampsilis leptodon, in form, texture, color, teeth and in gaping in front and behind. While [ know nothing whatever of the anatomy, I feel positive that the species do not belong to the Muitilide, for such vestigial teeth as they possess are dis- tinctly schizodont and not at all taxodont. The beak sculpture, though sometimes nodulous, shows more or less plainly con- centric ridges, and this would indicate that the genus belonged to the Exolvanchie. I believe that it is rather closely related to Chamberlainia, Pilsbryoconcha and Cristaria, and the fact that all its species are found in Tropical Africa does not seem to me to be any evidence against this, for the genera Nodularia and Parreysia are distributed over the two areas and the 4no- donta guillaini of Recluz, which is found in the Somali country in Africa, appears to be most nearly related to forms of south- eastern Asia, so that I have placed it in the genus Lamellidens. PSEUDOSPATHA 203 While none of these Oriental forms are very distinctly di- morphic as to shell characters, it may be remarked that in many species of the subgenus Proptera of Lampsilis the male and female shells are hardly distinguishable. Germain, (1. c.), however, refers the genus to the Wutelide. PSEUDOSPATHA TANGANYICENSIS (Smith). Shell irregularly rhomboid, thin to subsolid, compressed, gaping widely in front, on the anterior half of the base, and slightly behind, with a low, double posterior ridge ; a well-pro- duced right angled anterior wing and a low, posterior one; narrowed in front and rounded on the anterior base, the out- line full behind the center of the base, ending in a rounded or somewhat biangular point on the median line; truncated on the posterior slope ; beaks low, compressed, sculpture consisting of concentric ridges developed into rows of rather sharp pus- tules and showing the round, nepionic shell; surface with irreg- ular growth lines, copper-colored, sometimes rayed with green on the posterior half of the shell; left valve with a single un- even, low, somewhat lamellar pseudocardinal and one or two, more or less perfect, long laterals; right valve with a single pseudocardinal and one or two faint laterals; muscle scars shallow, with a couple of large scars placed at some distance from the hinge line and well behind the beaks; anterior scars irregular, impressed ; posterior scars faint; nacre purplish, soft and iridescent. Length 95, height 44, diam. 17 mm. Lakes Tanganyika and Nyanza, Africa. Spatha tanganyicensis SMitH, Proc. Zool. Soc. Lond., 1880, p. Ace pls Kxxiy fs S Burtonia tanganyicensis PavreL, Conch. Sam., III, 1890, p. 187. Pseudospatha tanganyicensis SIMPSON, Syn., 1900, p. 577-— GrerMAtNn, Moll. L. Tan., 1908, p. 684.—Arch. Zool. Exp. et Gen., (5), 1, 1900, p. 47, figs. 42, 43. Burtonia moineti Bourcutcnat, Un. and Ir. Tan., 1886, p. 33; Icon. Mal. Tan., 1888, pl. xxv, fig. 1. 204 PSEUDOSPATHA Burtonia lavigerina Bourcuicnat, Un. and Ir. Tan., 1886, p. 36; Icon. Mal. Tan., 1888, pl. xxiv, figs. 1-4. Burtonia magnipica Bourcuicnat, Un. and Ir. Tan., 1886, p. 41; Icon. Mal. Tan., 1888, pl. xxv1, figs. 1-2. Burtoma jouberti Bourcuicnat, Un. and Ir. Tan., 1886, p. 40. —GerMAIn, Moll. L. Tan., 1908, p. 685, figs. 37, 38.—Srmp- SON, Syn., 1900, p. 578. Burtoma foat MABILLE, Bull. Soc. Philom., III, 1901, p. 58.— GrrMAIN, Moll. L. Tan., 1908, p. 685, figs. 30, 40. The line between the valves is not exactly straight, and sometimes the posterior point is turned first to one side and then to the other. I am inclined to believe that the shells of this species are dimorphic and that Bourguignat’s Burtonia moineti, in which the posterior base is not inflated, is the male of this species, though it is possible that it may be distinct. The posterior slope shows slight traces of plication. PsEUDOSPATHA CARREI (Putzeys). Shell elongated, inequilateral, compressed, with a nearlv straight dorsal line; anterior end rounded, meeting the dorsal line at an obtuse angle; posterior end truncate above the base line, sweeping around from this truncation to the upper an- terior point in a long curve; beaks minute, slightly elevated above the dorsa! line; posterior ridge low but apparently well marked, ending behind in a rounded point on the median line: surface slightly concentrically rugose; epidermis fuscous-oli- vaceous, green at the umbonal region; nacre bluish, pearly and iridescent. Length 72, height 24, diam. 12.5 mm. Stanley Pool, Leopoldville, Congo. Burtonia carrei Purzrys, Proc. Verb. Soc. Mal. Belg., 1898, p. XxXviu, fig. 16. Mutelina carrei Germain, Arch. Zool. Exp. et Gen., (5), I, 1909, p. 58. Pseudospatha leopoldvillensis Stmpson, Syn., 1900, p. 577. PSEUDOSPATHA 205 At the time of publishing the Synopsis I had not been able to see the paper containing this species and the name was given erroneously in my work. The shell is something like P. livingstonensis, but the beaks are not placed nearly so close to the anterior end as in that species. PsSEUDOSPATHA LIVINGSTONENSIS (Bourguignat). Shell thin, compressed, elongated, when young, narrow be- hind and drawn out into a long beak; when old the dorsal and basal lines are nearly parallel and the shell is rhomboid; pos- terior ridge double; there is a posterior and anterior wing, below the latter the shell is slopingly truncate; surface pale coppery, slightly concentrically ridged; beaks low, compressed, with concentric sculpture, which becomes nodulous near the embryo, showing the nepionic shell; there is one pseudocar- dinal and one lateral in each valve; beak cavities shallow, with an irregular dorsal scar well behind the pseudocardinals ; ad- ductor scars shallow; nacre purplish, somewhat iridescent be- hind. Length 115, height 45, diam. 15 mm. Lake Tanganyika. Spatha tanganyicensis SMIYH (part), Proc. Zool. Soc. Lond., 1880, pl. xxx1, fig. 8a; 1881, p. 296, pl. x xxiv, fig. 32. Burtonia livingstonensis Bourcuicnat, Moll. Fluv. Nyanz., 1883, p. 20. , Pseudospatha livingstonensis SIMPSON, Syn., 1900, p. 578. Pseudospatha livingstoni GERMAIN, Moll. L. Tan., 1908, p. 686. Burtonia elongata BourGUIGNAT, Un. and Ir. Tan., 1886, p. 34; icone Mall Vans, 1588) pl: xxv, fis. 4. Burtonia contorta BourcuicNat, Un. and Ir. Tan., 1886, p. 39; Icon. Mal. Tan., 1888, pl. xxv1, figs. 3-5. Burtonia bridouxt BourcuicNat, Un. and Ir. Tan., 1886, p. 40.—Simpson, Syn., 1900, p. 578.—GERMAIN, Moll. L. Tan., 1908, p. 687, figs. 41, 42. The shell gapes considerably at the front and anterior base and slightly behind. The line of juncture between the valves 206 PSEUDOSPATHA is not entirely straight. Bourguignat’s Burtonia contorta is probably a specimen of this species which was injured and is on that account narrowed anteriorly. Until the shell has made a considerable growth its outline is exactly that of a livingston- ensis of the same age. PsEUDOSPATHA SUBTRIANGULARIS ( Bourguignat ). Shell trapezoidal, compressed, with a small projecting an- terior and a rather high post-dorsal wing; the dorsal line nearly straight: the posterior end obliquely truncate, with a low, double posterior ridge; surface with irregular, concentric growth lines, beautiful yellowish-chestnut, and faintly rayed before and behind; pseudocardinals wanting; laterals thick. Length 102, height 49, diam. 18 mm. Lake Tanganyika. Burtomia subtriangularis Bourcuicnat, Un. and Ir. Tan., 1886, p. 35; Icon. Mal. Tan., 1888, pl. xxv, fig. 2. Pseudospatha subtriangularis Simpson, Syn., 1900, p. 578. Burtonia grandidieriana Bourcutcnat, Un. and Ir. Tan., 1886, p. 42; Icon. Mal. Tan., 1888, pl. xxvut, figs. 1-3. PsSEUDOSPATHA BOURGUIGNATI (Bourguignat). Shell irregularly elliptical or obovate, subsolid, compressed, with a small, projecting anterior and a moderate posterior wing; dorsal line considerably highest at the middle, from which point it slopes in a straight line forward and back; out- line from the anterior point around the base to the posterior point nearly evenly curved, a little fuller behind the middle; beaks compressed ; surface splendid reddish-chestnut, the upper part of the umbonal region violaceous, interior violet and mag- nificently iridescent; pseudocardinals wanting; laterals solid. Length 81, height 42, diam. 20 mm. Lake Tanganyika. Burtonia bourguignati BourcuicNat, Un. and Ir. Tan., 1886, p- 38; Icon. Mal. Tan., 1888, pl. xxvit, figs. 4-5. Pseudospatha bourguignati SIMPSON, Syn., 1900, p. 578. HYRIOPSIS ZO7F Genus HYRIOPSIS Conrad, 1853. !lyriopsis CONRAD, Pr. Ac. N. Sci. Phila., 1853, p. 260. Shell large, compressed, rhomboid-elliptical, dorsally winged and generally biangulate behind, sometimes produced in the post-basal region ; beaks low, mostly compressed, the sculpture consisting of numerous concentric ridges, which are nearly parallel with the growth lines, generally extending well on to the disk of the shell, the earlier ones fine, often slightly nodu- lous or doubly looped; epidermis olive to brown, sometimes faintly raved; pseudocardinals two or three in the left valve, one to three in the right, when young compressed, but often breaking into irregular denticles when old; laterals long, com- pressed, two in the left valve and one in the right, sometimes vertically striate, the left valve often having a sort of raised lamellar tooth at or just behind the beak. Beak cavities shal- low; dorsal scars numerous, extending from the cavity down- ward and forward. Anterior muscle scars three, distinct, pos- terior large, indistinct ; front end of the shell usually thickened ; a row of plications often occurring just below the laterals, as in Cristaria. Animal unknown. Type, Unio delphinus Gruner. Group of Hyriopsis bialata. Shell somewhat trapezoidal, with a posterior ridge, biangu- late behind, with a very high, pointed, triangular, posterior wing, and a smaller, pointed one in front, which projects for- ward ; beaks low, sculpture not seen; epidermis brown; pseudo- cardinals broken up into denticles; hinge line slightly curved; the three anterior muscle scars separate and deep; dorsal scars not extending greatly downward in front; nacre bluish-white. HyRriopsis BIALATA Simpson. Shell elongated, subrhomboid, with a high, triangular pos- terior wing and a smaller anterior one, these wings are gen- erally broken off when the shell becomes old; subsolid, rather compressed; posterior ridge high, angular, with a faint sec- 208 HYRIOPSIS ondary ridge at some distance above it, the main ridge ends in a sharp point at the extreme post-basal part of the shell, the secondary ridge ends in an obtuse angle above it; liga- ment concealed in young shells, long and exposed in old ones; beaks low, their sculpture not known; epidermis black and somewhat shining, covered with scattered, low, pustule-like blisters, which are often arranged in concentric rows; left valve with a long, low, pinched up anterior pseudocardinal and a feeble posterior one, with two long, curved laterals; right valve with a long, irregular pseudocardinal, a small one above it and one lateral, all the pseudocardinals showing a tendency to break into denticles; beak cavities shallow, with an irreg- ular row of pits; anterior muscle scars distinct, well impressed, small; nacre bluish-white with a slight pallial sinus. Length 135, height, without the wing, 56, height with the wing 80, diam. 25 mm. Southeastern Asia, including Cambodia, Siam, and the Ma- lay Peninsula. Unio delphinus Gruner, Arch. fur Naturg., I, 1841, p. 276, pl. 1x, figs. 1, la-c.—DertLEssErt, Rec. Cog. Lam., 1841, pl. XIX, figs. 3, 3a, 3b.—Lea, Tr. Am. Phil. Soc., VIII, 1843, p. 218, pl. xvi, fig. 35; Obs., ITI, 1842, p. 56, pl. xvi, fig. 35: —Kuster, Conch. Cab. Unio, 1852, p. 18, pl. 1, figs. 2-4.— Hantey, Biv. Shells, 1856, p. 381, pl. xx, fig. 44—-CHENU, Man., 1850, II, p. 143, fig. 707——SoweErBy, Conch. Icon., XVI, 1866, pl. x11, fig. 238. Margaron (Unio) delphinus Lea, Syn. 1852, p. 19; 1870, p. 28. Metaptera delphinus Morirr, J. de Conch., XXXVII, 1889, p. 165. Unio megapterus Moreiet, J. de Conch., XII, 1863, p. 159. Hyriopsis bialatus Stmpson, Syn., 1900, p. 579. Unio delphinepterus DAUTZENBERG and Fiscner, J. de Conch., LIII, 1905, p. 456. A most striking species, having when young and perfect a very high wing. Gruner’s name was used previously by Spengler for a Unio and the term megapterus of Morelet was applied by Rafinesque to a Metaptera (Unio) and used by Chenu under the generic name Unio before 1863. The scattered pustules, like blisters, is a peculiar feature. MHYRIOPSIS 209 Hyriopsis Gractiis (Haas). “Shell long, narrow, alate, rather solid. Anterior end very short; the superior margin somewhat curved in front and drawn out in a horizontal or bent up point, meeting the anterior margin at a distinctly sharp angle; anterior margin concave above, slightly convex below as it passes into the almost hori- zontal, slightly convex basal margin: posterior end rounded and slightly biangulated ; posterior margin oblique ; wing near- ly one-half the height of the shell, concave behind, rounded at the end and nearly straight in front, meeting the dorsal margin at an angle of 45° a short distance behind the beaks. Beaks anterior, placed at 19/100 of the total length, not pro- jecting nor swollen, sculptured with a few, concentric, wavy wrinkles. From the beaks to the biangulations of the posterior end extend two feeble, thread-like lines, which become lower posteriorly. Ligament strong, covered by the wing. Cardinal teeth weak; two in the right valve, the inner one lower and lamelliform, the outer one subobsolete, lamelliform ; in the left valve a rather stouter, lamelliform tooth, in front of two feeble ridge-like teeth; lateral teeth long, straight, two in the left and one in the right valve. Angle of the cardinal teeth 40° ; angle of the lateral teeth 0°. Nacre bluish-white. Muscle impres- sions weak. Epidermis black-brown or brown-green, eroded on the beaks. Length r1o, greatest height 68, height at the beaks 30, height of the wing 27, diam. 19 mm.” (Haas.) Type locality, Bienho-Sei, Mekong. Hyriopsis gracilis Haas, Nachr. Deutsch. Mal. Ges. VOLO a 101. Group of Hyriopsis cumingit. Shell rather thin, with a high wing posteriorly and a smaller one in front; beaks greatly compressed, their sculpture at first consisting of fine and later of coarse concentric ridges, which extend well on to the disk; corrugations on the posterior slope distinct. 210 ITYRIOPSIS Hyriopsis CUMINGII (Lea). Shell large, rhomboid or trapezoid, with a sharp pointed anterior wing and a very high, somewhat irregular posterior wing; rather thin or only subsolid; compressed, with low, much compressed beaks, which are sculptured with numerous strong ridges that nearly follow the growth lines and extend well out on to the disk; surface shining, the posterior wing and hinder part of the shell sometimes corrugated by irregular grooves; folds of the posterior slope distinct ; color brownish or yellowish-green with numerous rays; epidermis shining ; left valve with two small, compressed, rather elevated and nearly vertical pseudocardinals, the anterior higher, and two long, curved laterals; right valve with two pseudocardinals, the posterior higher, and one lateral; beak cavities very shal- low, showing a diagonal row of scars; adductor scars shallow, the anterior ones small; pallial line very far removed from the shell border; nacre bluish-white, with purple and green iri- descence behind. Length 134, height, without wing 80, with wing 117, diam. 18 mm. China. Unio cumingti Lea, Pr. Ac. N. Sci. Phila., VII, 1852, p. 54.— Jl. Ac. N. Sci. Phila., IV, 1860, p. 240, pl. xxxv, fig. 120; Obs., VII, 1860, p. 58, pl. Xxxv, fig. 120.—Sowersy, Conch. Icon., XVI, 1866, pl. xix, fig. 264—Hxrupe, Conch. Fluv. Nank., VIII, 1883, pl. xiv. Margaron (Umo) cumingn Lea, Syn., 1852, p. 19; 1870, p. 28. Hyriopsis cumingtt Simpson, Syn., 1900, p. 579. Hyriopsis. goliath Route, Nachr. Deutsch. Mal. Ges., 1904, p. 25, pl. 1 and 11.—DauTzeNnBERG and FiscHer, J. de Conch., EAT, 2905; p. 201. _ea’s larger shell, the one whose dimensions are given above, is evidently young and probably a female, as it is slightly swollen at the post-basal part. He has a somewhat younger shell which is straight on the basal line. HYRIOPSIS 211 Hyrtopsis DELAPORTEI (Crosse and Fischer). Shell with a high, irregular posterior wing, which is often curled over at the top, and a smaller anterior wing like that of a Prisodon, the median dorsal line nearly straight, showing a part of the ligament, somewhat triangular, subsolid, scarcely inflated, with a rather high, sharp or angled posterior ridge; beaks compressed, their sculpture consisting of 7 or 8 bars running parallel with the hinge line; epidermis pale, yellow- ish-green or greenish-brown, scarcely shining; left valve, when young, with two long, compressed pseudocardinals and two curved laterals; right valve with two pseudocardinals and one lateral; in some of the young there are three pseudocar- dinals in each valve. As the shell grows older these break up into vertical ridges and the laterals are shortened and be- come remote; beak cavities shallow with an irregular row of pits; anterior scars impressed; posterior scars faint: nacre bluish-white, often blotched and dull. Length 130, height, without wing 70, with wing too, diam. 35 mm. Cambodia, Siam. Unio (Arconaia) delaportet Crosse and FiscurEr, J. de Conch.. ROXIE S70. pe 227, ple he rs ply KIS fio. 5. Arconaa delaportei Morier, J. de Conch., XXXVII, 1880, p: 165. Hyriopsis delaportet Stmpson, Syn., 1900, p. 580. The line of junction between the valves is not straight but somewhat flexuous and the anterior or posterior end of the shell may be flexed a little to the right or left, hence Crosse and Fischer placed the species in Arconaia. There is a slight anterior and posterior gap to the shells as in so many of the winged American forms, and the shells seem to be somewhat dimorphic. In two of the U. S. Nat. Museum specimens there is quite a post-basal inflation and the posterior point is elevated above the base line. In another the base line is a little incurved medially and the posterior point is not at all raised. There are traces of plication on the post-dorsal region in most shells and the escutcheon is very large. 2%t2 HYRIOPSIS Group of [Hyriopsis myersiana. Shell rather solid, thickened in front; posterior ridge rather low ; beaks compressed, the sculpture consisting, apparently, of a few rather faint, irregular ridges, sometimes slightly nod- ulous. HyRrIopsiS MYERSIANA (Lea). Shell large, elliptical or obovate, subcompressed or com- pressed, solid when old, with a small anterior wing and a high, ragged posterior wing when young, which is lost in old age; posterior ridge well developed, sometimes angulated, and there are often one or two faint ridges on the posterior slope ; beaks low, raised a little above the hinge line, subcompressed, with faint, horizontal ridges, occasionally slightly nodulous; left valve with two or three compressed, elongated, somewhat un- even pseudocardinals and two curved laterals; right valve with two pseudocardinals, the lower higher, and one lateral ; when the shell becomes old the laterals are remote and the pseudocardinals become split across into numerous irregular denticles: beak cavities shallow; muscle scars of the cavities in'a diagonal row; anterior adductor scars small, impressed: posterior scars shallow ; nacre white or flesh-colored, often iri- descent. The shells generally end in a wide, faint biangulation behind; in some of these the biangulation is mostly below the median line, and the post-basal line is not much extended ; in others the point is midway up the shell and there seems to be a marsupial swelling. Length 165, height 95, diam. 45 mm. Siam ; Cambodia. Unio myersianus Lea, Pr. Ac. N. Sci. Phila., VIII, 1856, p. 2; Jl. Ac. N. Sci. Phila., III, 1857, p. 290, pl. xx11, fig. 2; Obs., VI, 1857, p. 10, pl. xx11, fig. 2—Sowersy, Conch. Icon., XVI, 1866, pl. 1, fig. 265. Margaron (Unio) myersianus Lea, Syn., 1870, p. 28. Metuptera myersianus Moret, J. de Conch., XXXVI, 1889, p., FOS; Hyriopsis myersianus Simpson, Syn., 1900, p. 580. HYRIOPSIS 213 Unio. housei Lea, Pr. Ac. N. Sci. Phila., VIII, 1856, p. 92; jl Aen: SctipPhila.; FLL. 1858,\p) 201, pl xxii, fig. 3; Obs., VI,..1857, p. 11, pl. xxi, fig. 3—Sowersy, Conch. Icon., XVI, 1866, pl. xivitt, fig. 260. Margaron (Umo) housei Lea, Syn., 1870, p. 28. The epidermis is olive-green when young and brown in the adult shell; in old specimens the nacre is very thick anteriorly. A single old valve in the Lea collection is 185 millimeters in length, and its pseudocardinals are heavy and consist of strong, irregular cross ridges; the laterals are short and remote. Unio housei of Lea is, I am sure, only the young of the above. There are scarcely any traces of plications on the posterior slope. ! ie Hyriopsis SUTRANGENSIS (Morlet). ee: Shell large, obovate and subrhomboid, thick, subinflated, with a blackish epidermis, which is concentrically striated and lamellate behind; hinge and basal line slightly curved; behind the hinge the shell is angled, and below this it is obliquely truncated and sinuous; anterior end rounded and narrowed ; posterior ridge low; beaks well forward, their sculpture not observed; right valve with two rather short, thick, crenulate pseudocardinals and one long, thin lateral; left valve with one pseudocardinal and two laterals; anterior muscle scars deep, with two well-marked, smaller scars at each; posterior scars shallow ; dorsal scars five or six; nacre whitish, bluish behind. Length 140, height 62, diam. 34 mm. Sutrang River, Siam. Unio sutrangensis Moret, J. de Conch., XX XVII, 1889, p. 1O5., pla tk, 1S 3° Ayriopsis sutrangensis SIMPSON, Syn., 1900, p. 580. This species probably belongs in the genus Hvyriopsis, though Morlet believes it to be near to Unio scutum. Nothing is known of its beak sculpture. HyRIOPsis FULVASTER (Drouet and Chaper). Shell elliptic, subrhomboid, rather short, subinflated, thin, inequilateral ; post-dorsal part somewhat elevated, and almost wing-like; anterior end somewhat narrowed, truncate above, 214 HYRIOPSIS rounded below; base curved, a little fuller behind the middle: dorsal slope almost squarely truncated; lower posterior out- line rounded; posterior ridge low, rounded; beaks scarcely elevated ; hinge line somewhat curved; teeth compressed ; lat- erals prominent behind; nacre pale bluish, rose-tinted, with livid blotches in the cavities. Length 38, height 28, diam. 15 mm. Kapoeas, Borneo. Unio fulvaster Drourr and CHapger, Mem. Soc. Zool. Fr., V, 1892, p. 154, pl. vi, figs. 11-13. Nodularia fulvaster SIMPSON, Syn., 1900, p. 819. Contradens fulvaster HAAs, Conch. Cab., 1912, pl. 20, figs. 4-5. Probably a young shell, and I cannot be sure as to its rela- tionship. In the Synopsis I placed it in Nodularia, but I am now inclined to believe it may be an Hyriopsis. The authors state that the beaks of their shell are eroded and make no men- tion of any sculpture on the disks. The color seems to be a light brown. Hyriopsis PINCHONIANA (Heude). Shell subsolid, almost regularly elliptical, compressed, with a low, somewhat double posterior ridge; beaks slightly ele- vated, their sculpture not observed; dorsal region having ves- tiges of posterior wing; epidermis yellowish-brown with faint, green rays; pseudocardinals compressed, apparently one in the right valve and a feeble lamina above it; anterior muscle scars impressed ; nacre pale salmon-color, somewhat iridescent. Length 63, height 35, diam. 15 mm. Tch’eng-tou fou, Province of Se-tchouan, China. Unio pinchonianus Hrupr, Conch. Fluv. Nank., VIII, 1883, pl. Lx, fig. 12. Hyriopsis pinchonianus Simpson, Syn., 1900, p. 580. The specimen figured by Heude is nearly evenly elliptical in outline, showing traces of bianguation behind, and having a curved base line. The figure shows ragged traces of a post- dorsal wing. HYRIOPSIS 215 Group of Hyriopsis vagula. Shell elliptical, with a rather high, posterior wing, moder- ately solid, with two slight posterior ridges and a sulcus above them at the juncture of the wing: Hyriopsis VAGULA (Fischer). Shell irregularly elliptical or subrhomboid, subcompressed, solid, with a low, curved posterior ridge; beaks full and in- flated for a member of this genus, their sculpture not seen; surface rich olive-brown; dorsal line nearly straight; outline of posterior slope truncated, ending in an obtuse angle at the summit of the wing; anterior end of the shell rounded ; pos- terior end more narrowly rounded: base evenly curved; nacre whitish-salmon in the cavity of the shell. Length 100, height over all 80 mm. Siam. Unio subtrigonus Sowrersy, Conch. Icon., XVI, 1867, pl. Lviu, fig. 292. Margaron (Unio) subtrigonus Lua, Syn., 1870, p. 28. Unio (Monocondylea) cambojensts Sowrrsy, Conch. Icon., XVI, errata. Pseudodon cambojensis Morrie, Ser. Conch., EVES 1S7.625/p: 330. Unio lamellatus HANtey and TuHerosarp, Conch. Ind., 1876, pe 5p plies tren, O: Unio vagulus Fiscurr, Bull. Soc. Autun., IV, LSOrs -p, 223) Hyriopsis vagulus Simpson, Syn., 1900, p. 580. The above description is taken from Sowerby’s figure and description. Sowerby says nothing whatever of the teeth or muscle scars, and I cannot therefore be certain as to its sys- tematic position, but believe with Fischer that it is near the Unio myersianus Lea. Sowerby published the species in the Conchologia as Unio subtrigonus, but the name was preoccu- pied by Deshayes. In the errata he changed it to Unio (Mon- ocondylea) cambojensis, believing it to equal Petit’s species. Tt is certainly not that shell and I therefore accept Fischer’s name for it. 216 HYRIOPSIS Group of Hyriopsis velthwezent. Shell somewhat inflated, rather thin, rounded behind, winged; epidermis dark brown with numerous green rays; nacre iridescent, bluish-white; anterior scars irregular, rather small; posterior scars rounded ; pseudocardinals elongated, one in each valve, in the right valve there being a secondary rudi- mental one; laterals elongate, arcuate, one in the right valve and two in the left. Hyriopsis VELTHUIZENI (Schepman). Shell subtriangular, thin, scarcely inflated, with a well-de- _ veloped, rounded posterior ridge, which is slightly double and biangulate, the lower ridge the most distinct ; with a high, thin, posterior wing, which is rather acutely angled behind and a small, obtusely angled anterior one; base line nearly straight, sometimes feebly incurved in the middle; surface finely, irreg- ularly, concentrically striate, shining, vellowish-olive, faintly rayed ; beaks low, sculpture not seen; left valve with one pseu- docardinal and two nearly straight laterals; right valve with one pseudocardinal, a small one above it, and one lateral ; teeth all lamellar; muscle scars feeble; nacre bluish, tinted purple, iridescent, especially on the wings. Length 65, height 30, to summit of wing 53, diam. 20 mm. The above measurements are from what is probably a young shell. Mandai River, Borneo. Unio velthnizeni ScurpmMan, Notes Leyden Mus., XVII, 1895, p. 160, pl. rv, figs. I, Ia. Hyriopsis velthuzeni Simpson, Syn., 1900, p. 581. This shell suggests an extremely close relationship to such species as Lampsilis alata and its variety poulsoni or the L. inflata. Group of Hyriopsis schlegeli. Shell rather thin, slightly winged behind, narrowly rounded before and angled at umbonal slope; posterior ridge high and rounded; beaks rather low; epidermis rough, blackish; hinge HYRIOPSIS 217 line curved in front, straight behind ; pseudocardinals generally entire; plications below the laterals faint; nacre dull lurid purplish or lead-color. Hyriopsis SCHLEGELI (von Martens). Shell large, irregularly long-ovate, subsolid, rather com- pressed, slightly gaping before and behind, with a well-de- veloped, somewhat biangular, posterior ridge; beaks low, ap- parently compressed, but very deeply eroded in all the speci- mens seen; there is a faint post-dorsal wing and from this the shell is obliquely truncate behind; epidermis showing concen- tric growth lines, very thick and black, having a tendency to crack off ; left valve with two low, radial pseudocardinals; the right valve has one and they show a tendency to split up into radial denticles; there are two remote straight laterals in the right valve and one high truncated one in the right; beak cav- ities shallow, with a row of pits pointing towards the anterior end of the shell; muscle scars well impressed, the anterior ones distinct ; pallial line deep in front; nacre dirty lurid whitish, generally with large, darker blotches, much thicker for a short distance in front. ‘The limited amount of material I have seen does not justify me in saying that the shells of this species are dimorphic. Length 200, height 100, diam. 50 mm. Japan. Umo schlegeli von Martens, Mal. Blatt., VII, 1861, p. 55.— Kosett, Abh. Senck. Nat. Ges., XI, 1879, p. 421, pl. x1v.— von Martens, Nov. Conch., V, 1879, p. 192, pl. cLv1t, figs. 4, 5. Barbala schlegeli Pret, Conch. Sam., III, 1890, p. 175. Hyriopsis schlegeli Stmpson, Syn., 1900, p. 581. A very large, elongated, compressed and rather unattractive species, which is not very closely related to any other known form. There are traces of plications on the posterior slope. 218 HYRIOPSIS Subgenus CAupICULATUS Simpson, 1900. Caudiculatus SIMPSON, Syn., 1900, p. 581. Shell oval, inflated, slightly posteriorly winged, with a well- developed posterior ridge and above it a deep, wide furrow ending in a broad, well-defined notch on the posterior slope; one pseudocardinal in the right valve and two in the left; two laterals in the left valve and one in the right. Animal un- known. Type, Unio caudiculatus yon Martens. HyRIOPSIS CAUDICULATA (von Martens). Shell oval, much inflated, very inequilateral, rather smooth, with only slight wrinkles and numerous fine, concentric stria ; beaks prominent, decorticated in the specimens examined ; ept- dermis dark brown with a metallic luster, somewhat velvety near the extremities ; upper margin slightly curved posteriorly, straight anteriorly ; anterior margin rounded, passing’ insensi- bly into the convex ventral margin; posterior margin oblique above, with an obtuse angle near the superior one ; somewhat below the middle of its length it is deeply and widely emargin- ate; posterior end widely truncated; from the edges of this truncation two low posterior ridges run towards the beaks; nacre blue, iridescent near the free margins, olive-yellow near the beaks ; hinge strong’; teeth irregular, thick; there is a cren- ulated pseudocardinal in the right valve and two nearly con- solidated ones in the left; two nearly straight laterals in the left valve and one in the right; anterior scars irregular, deep; posterior scars shallow; pallial line distinct. Length 67, height 47, diam. 29 mm. Small. brook near Singangi in the Ketoengau District, sorneo. Unio caudiculatus von Martens, Mal. BI., XIV, 1866, p. 16. Unio infrarostratus ScuepMAN, Notes Leyd. Mus., XVII, EeO5, 40.101, pl. iv, fie. 2: Hyriopsis caudiculatus SIMPSON, Syn. 1900, p. 581. Caudicalatus caudiculatus Haas, Conch. Cab., 1912, pl. 18, fig. 1. I have never seen this species and have considerable doubt as to its relationship. It is placed in Hyriopsis provisionally. CHAMBERLAINIA 219 Genus CHAMBERLAINIA Simpson, tgoo. Chamberlainia SIMPSON, Syn., 1900, p. 582. Shell large, very solid in front, thinner behind, round or round obovate, with low posterior ridge, alate on the post- dorsal part when young; beaks full, sculpture not seen: sur- face without sculpture excepting a few slightly pustulous cor- rugations on the posterior slope; epidermis dull, not rayed; hinge curved; pseudocardinals rather small, stumpy, two in the left valve and one in the right; laterals short, remote, the intervening hinge plate rounded, one lateral in the right valve and two in the left, the upper the smaller, and all curved up- ward along their inner edges; beak cavities not deep; dorsal muscle scars numerous, deep, extending from the cavity down- ward and forward; area outside the pallial line very wide; nacre lurid bronzy. Animal unknown. Type, Unio hainesianus Lea. CHAMBERLAINIA HAINESIANA (Lea). Shell short obovate, solid, subcompressed, with moderately high, subcompressed beaks, from which a rounded posterior ridge runs out a short distance on to the disk and vanishes ; there is a very small anterior and a moderate posterior wing, which is corrugately plicate; a slight radial sinus runs from the beaks to the posterior part of the shell just above the median lines; epidermis warm brown, rather dull: left valve with two small, erect pseudocardinals and two remote laterals, the upper the smaller, both having the inner edges reflexed ; right valve probably having one pseudocardinal and one lat- eral ; beak cavities moderately deep, with a row of scars under the pseudocardinals; anterior muscle scars rough, impressed ; posterior scars shallow ; nacre white and very thick at the an- terior base, the rest lurid, somewhat iridescent behind ; pallial line a long way from the border of the shell. Length 203, height 150, diam. 78 mm. Siam. 220 CHAMBERLATINIA Unio hainesianus Lea, Pr. Ac. N. Sci. Phila., VIII, 1856, p. 92; Jl. Ac. N. Sep, Pinal. TT, WSn7. sp oR gl see tasers Obs., VI, 1857, p. 9, pl. xx1, fig. 1—Sowerpy, Conch. Icon., XVI, 1866, pl. xivun, fig. 254. Margaron (Unio) hainesianus Lea, Syn., 1870, p. 28. Chamberlainia hainesiana Simpson, Syn., 1900, p. 582. Unio imperialis Moreirr, Rev. et Mag. Zool., XIV, 1862, p. 480. The type consists of a single valve of a young individual. U. imperialis, according to its author, attains a size of 142 mm. in height, 192 mm. in length, and 77 mm. in diameter. I have seen a very fine specimen in the Frederick Stearns collection 6 inches high and 8 in length. It is one of the most magnifi- cent Naiades in the world. CHAMBERLAINIA PAVONINA Rochebrune. “Shell thick, heavy, subtrigonal, inequilateral, slightly com- pressed, slightly gaping; olive-brown, subshining ; deeply con- centrically sulcate, sulci here and there subfoliaceous; dorsal margin oblique; anterior round, obtusely subrostrate; poste- rior abruptly truncate, subalate, faintly triangular; basal mar- gin broadly convex; beaks eroded, subcontiguous, rounded, situated at about one-fifth of the length; disk flattened, with broad, undulating, slightly spreading plications; ligament heavy, short, curved, somewhat covered ; interior whitish-blue, more or less pearly, deep coppery and iridescent posteriorly. Length 175, height 134, diam. 65 mm.”’ (Rochebrune. ) Type locality, Battambang, Province of Salabury, Siam. Chamberlainia pavonina RoCHEPRUNE, Bull. Mus. Hist. Nat., 1904, p. 464. “This form, while close to Chamberlainia hainesiana, differs by its less trapezoidal, more ovoid shape, by the more rounded anterior end, by the greater convexity of the basal margin, by the aliform expansion of the posterior margin being more tri- angular and less rounded, the more anterior beaks, which are less acute, by the pseudocardinals stronger, more massive pro- portionally and more deeply crenulate and finally by the longer and more prominent teeth.” SIMPSONTA 221 CHAMBERLAINIA PAVIEI (Morlet). Shell subtriangularly orbicular, inequilateral, very slightly convex, with faint, concentric strie and a thin yellow-green epidermis ; beaks pointed, decorticated in the shells examined: anterior end rounded below, angled at its junction with the dorsal line; dorsal wing rather high, angled behind; right valve with two solid pseudocardinals and one curved lateral, the hinge line being much narrowed and curved in front of it ; nacre pale yellowish or whitish. Length 67, height 65, diam. 25 mm. Siam. Unio pazrei Morir, J. de Conch., XXXIX, 1891, pl. vu, fig. 3. Chamberlainia paviei Simpson, Syn., 1900, p. 582. Chamberlainia pavici ROCHEBRUNE, Bull. Mus. Hist. Nat., 1904, p. 463. Morlet does not give the number of the teeth in each valve, but those of the right valve are shown in his figure. ‘The shell seems to be close to that of C. hainesiana, but is more triangu- lar in outline. Rochebrune, (1. c.) states that the series in the Museum d’Histoire Naturelle show that this species is the young of C. hainesiana. Genus SIMPSONIA Rochebrune, 1904. Stmpsonia ROCHEBRUNE, Bull. Mus. Hist. Nat., 1904, p. 465. “Shell elongate-ovoid; very thick, heavy, with a slight pos- terior wing; strongly sulcate; beaks thick, obtuse, subcontig- uous, their cavity quite deep; ligament short, wide, subobtuse ; pseudocardinals, two in the left valve, not large, compressed, separated by a broad, concave, six-dentate interval, one in the right valve, very large, quadrate, deeply bisulcate; laterals short, very heavy, one in the right valve, very wide, high, rounded above, two in the left valve, of equal length, very short, acute, in the form of a letter X: muscular impressions deep, rugosely sulcate; pallial line deep, very wide in front.” (Rochebrune. ) Type, Unio duclerci Rochebrune. 222 SIMPSONIA SIMPSONIA DULCLERCI (Rochebrune ). Shell subrhomboid, somewhat lenticular, solid, scarcely in- flated, sometimes subcompressed ; posterior ridge low and very wide, slightly biangulate ; beaks not high nor full, their sculp- ture not seen; surface with irregular growth lines; epidermis apparently olive-green; there is a low posterior wing, which is worn away in old shells; hinge line nearly evenly curved; left valve probably having two pseudocardinals and two lat- erals; right valve with one strong, triangular, high pseudocar- dinal, with a vestige of a small one in front of it, and one remote, short, truncated lateral, which is decidedly reflexed along its inner edge; the hinge line is smooth and rounded be- tween the two teeth; beak cavities deep, with a row of pits under the pseudocardinal ; muscle scars impressed, the anterior roughened: nacre whitish, clouded with purplish-brown, soft and shining, very thick in front; pallial line deep. Length 122, height 90, diam. about 45 mm. Mekong River, Siam. Umio duclerci RoCHEBRUNE, Bull. Soc. Phil., VII, 1882, p. 27, pl) a, fis. 2 (im extract )- Chamberlainia duclerci StMpson, Syn., 1900, p. 582. Simpsonia duclerci RocHEBRUNE, Bull. Mus. Hist. Nat., 1904, p. 465. Two right valves much worn and eroded were donated to the National Museum by Mr. John B. Henderson, Jr. The short lateral is reflexed as it is in .epidodesma and the nacre, which is peculiarly clouded, is very greatly thickened in front. SIMPSONIA DEMANGE! Rochebrune. “Shell very thick, compressed, elongate-ovate, inequilateral, gaping in front, with a slight posterior wing; laminately, con- centrically sulcate, deeply eroded, dark blackish-brown, irreg- ularly radiately costate, with broad, flat, interrupted folds; dorsal margin almost straight, slightly oblique, anterior mar- gin small, rounded and somewhat produced; posterior margin subtriangular, subcompressed; basal margin the longest, al- most straight, slightly undulated; beaks small, compressed, CRISTARIA 223 subcontiguous, placed at about 1/7 of the length; area small; ligament very long, thick, very black; interior pearly, tinged with pale rose. Length 240, height 169, diam. 75 mm.” (Rochebrune. ) Type locality, Riviere Claire between Vietri and Tuyen- Quas, Tonkin. Simpsonia demangei RocHesrune, Bull. Mus. Hist. Nat., 1904, p. 465. Genus CRISTARIA Schumacher, 1817. Barbala Humpureys, Mus. Col., 1797. Dipsas Leacu, Zool. Miscellany, I, 1815, p. 119. Cristaria SCHUMACHER, Essai Nouv. Syst., 1817, p. 107. Appius (LeacH), Menke. Syn., 2d ed., 1828, ? p. 106. Symphynota LEA (part), Tr. Am. Phil. Soc., 1830, p. 445. Diamsotis RAFINESQUE, Cont. Monog., 1831, p. 7. Dipsax Voict, Cuvier, Thierreich, III, 1834, p. 493. Barbata Sowersy, Conch. Man., 1842, p. 81. Clone GisteL, Nat. Sur. Hoh. Schule Bearb., 1848. Shell generally thin, elliptical, more or less winged poste- riorly ; beaks rather low, sculptured with fine, somewhat doubly- looped ridges at first, and later with coarse, low, concentric bars, which are nearly parallel with the growth lines; epider- mis smooth, often somewhat raved; hinge teeth imperfect ; pseudocardinals feeble or wanting—when present consisting of a single compressed tooth in each valve; laterals single, re- mote, compressed, sometimes wanting in adult shells. Type, Dipsas plicatus Teach. Subgenus CRISTARIA S. S. Shell large, thicker in front, strongly alate posteriorly, with two or more slightly developed radial ridges on the posterior slope and a row of plications above them; hinge line regularly curved: dorsal scars forming a row running obliquely down- ward and forward; anterior scars often blurred, posterior faint. 224 CRISTARIA CRISTARIA PLICATA (Leach). Shell very large, somewhat rhomboid, thin or subsolid, not inflated, with low, compressed beaks, whose sculpture consists of a few feeble ridges running nearly parallel with the growth lines and fading out at the posterior ridge; posterior ridge rather high and rounded in the earlier stages of growth, nearly obsolete below on older shells ; there is a sharply angled, some- times elevated wing in front and a high one with an irregular dorsal border behind ; surface greenish-yellow to pale or brown- ish-olivaceous, faintly rayed in the young shells ; posterior dor- sal plications strong, showing inside and out and extending from the beaks to the hinder end of the laterals; post-dorsal region obliquely truncate, the outline straight in young: shells, incurved in old ones; posterior end sometimes slightly biangu- late; escutcheon large; each valve has a single short lateral; beak cavities shallow, with a row of scars pointing towards the anterior base; muscle scars shallow, the anterior irregular ; nacre dull whitish, often blotched, thicker in front in old shells. Length 230, height including wing 176, without wing 142, diam. 60 mm. China; Japan; Amurland, south probably to Cambodia. Dipsas plicatus Lwacu, Zool. Miscellany, I, 1815, p. 120, pl. Lit.—Sowersy, Conch. Man., 1839, fig. 142—-CHENU, Bib. Conch., 1st ser., III, 1845, p. 15, pl. v1, fig. 1—HeEupg, Conch. Fluv. Nank., 1879, pls. XXXIII, XXXIV, LI, fig. 94. Mytilus plicatus SoANpDeER, in Gray, Ann. of Phil., IX, 1825, p. 27. Appius plicatus Gray, in Menke, Syn. Meth, Moll., 1830, p. 106. Margarita (Dipsas) plicatus Lea, Syn., 1836, Pp. 47; 1838, p. 28. Margaron (Dipsas) plicatus Lua, Syn., 1852, p. 46 ; 1870, p. 74. Unio plicatus Sowerby, Conch. Icon., XVII, 1868, pl. Liv, fig. 280. Dipsas plicata Kopx.r, Abh. Senck. Nat. Ges., XI, 1879, p. 429, pls. XV-XVII, XVIII, fig. T. CRISTARIA 225 Barbala plicata H. and A. Apams, Gen. Rec. Moll., IT, 1857, p. 501, pl. cxvul, figs. 4, 4a. Anodonta plicata ScurencK, Reis. und F. Am. Lande, IL, 1867, p. 704, pl. xxvu, fig. 4. Anodonta (Dipsas) plicata Ciessin, Conch. Cab. Anodonta, 1876, p. 240, pl. xx1, figs. 1, 2. Cristaria plicata von IneRtING, Abh. Senck. Nat. Ges., XVIII, 1893, p. 147.—Simpson, Syn., 1900, p. 583. Cristaria tuberculata ScHumacuer, Ess. Nov. Syst., 1817, p. 140, pl. xx, fig. 2. Anodonta dipsas Biarnvittx, Man. Mal., 1825, p. 538, pl. XVI, fips 2: Symphynota bialata Lea, Tr. Am. Phil. Soc., 1830, p. 445, pl. XIV, fig. 24; Obs., I, 1834, p. 59, pl. xiv, fig. 24. Unio bialata Hantexy, Biv. Shells, 1843, p. 214, pl. xxu1, fig. 4. Barbala bialata Cuenu, Man., 1850, p. 145, fig. 717. Unio bialatus Drsuayrs, ‘Ir. Elem. Conch., 1839, p. 19, pl. XxXxI, fig. 3; Tr. Elem., II, 1853, p. 218, pl. xxxz, fig, 3.— Sowersy, Conch. Icon., XVI, 1868, pl. xuvi, fig. 247. Anodonta magnifica CLesstn, Conch. Cab. Anodonta, 1873, p. 123;, pl. RxXv; fig: £. Barbala plicatula Paver, Conch. Sam., ITT, 1890, p. 175. I cannot say that the shells of this species are dimorphous, though there are specimens which are fuller in the posterior base than others. There is a considerable variation in the form, some of them having a slightly rounded basal line; in others it is incurved a little; some are considerably narrower in front while others are no wider behind, (leaving out the wing), than they are at the anterior end. ‘There is frequently a single faint pseudocardinal in each valve. The form from Cambodia, which is referred to C. plicata, is believed by Fischer to be different, and it may be C. bellua. CRISTARIA OCCIDENTALIS (Heude). Shell long elliptical, rather solid, subinflated, with a small anterior wing and a larger irregular dorsal one: beaks sub- compressed, their sculpture consisting of very faint, concen- 226 CRISTARIA tric ridges; plications of the posterior slope few and small; posterior ridge very full and rounded on the earlier growth but fading out entirely in its later stages; posterior end nearly evenly rounded, very slightly pointed at the median line; cen- ter of the disks smooth, the epidermis around the border con- centrically roughened, pale brownish in the center of the disks, darker around the border; pseudocardinals wanting; laterals feeble, one in each valve; beak cavities shallow with a row of pits pointing towards the anterior base; anterior scars ir- regular; posterior scars shallow; nacre in the cavity of the shell brownish, tinted with purple; that of the posterior end iridescent ; the nacre of the anterior end and base is very solid and milky-white ; prismatic border wide. Length 135, height without the wing 80, with the wing 95, diam. 43 mm. Western Se-tchouan, China. Dipsas occidentalis Hrupe, Conch. Fluv. Nank., IX, 1885, pl. ICV. Barbala occidentalis Pazret., Conch. Sam., III, 1890, p. 175. Cristaria plicata (part), Stimpson, Syn., 1900, p. 583. In the Synopsis I placed this species in the synonymy of C. plicata, but additional study of the Cristarias and the examin- ation of an author’s specimen incline me to think that, though very close to that species, it may be distinct. The beak sculp- ture is much more feeble, as are the posterior plications, the shell is more inflated, the posterior ridge is much fuller and the nacre is brighter than in that species. ‘The nacre around the anterior border is very solid, more so than in any Cristaria I know. Its outline is very much like that of plicata. CRISTARIA BELLUA (Morelet). Shell somewhat trapezoidal, subsolid, slightly inflated, with a high, widely rounded posterior ridge, which extends to the extreme hinder point ; beaks low, the umbonal region but little inflated, with about six wide, low, concentric ridges ; posterior slope with a few folds, which show within and without; an- terior and posterior dorsal wings moderate, the upper dorsal CRISTARIA 227 line of the shell being nearly straight; growth lines irregular, becoming almost sulcate on the border of the shell; epidermis dark chestnut or blackish, shining in the middle of the disk; hinge line arched ; there is a short curved lateral in each valve; pseudocardinals wanting or indicated by a mere raised line; escutcheon square; beak cavities shallow, with a few deep pits; anterior muscle scars irregular; posterior scars some- what crescentic, their upper points reaching to the posterior ends of the laterals; nacre bluish-white, milky. Length 140, height 100, diam. 60 mm. Cambodia. Anodonta bellua More.et, Rev. et Mag. Zool., XVIII, 1866, p. 167. Cristartia bellua Simpson, Syn., 1900, p. 584. Compared with C. plicata, this species is more rhomboid, more inflated, and drawn out behind into a more decided point, this point being nearer the base line than in flicata, and its epidermis is more chestnut and not so much olive-colored. Its nacre is milky-white, that of plicata is not. The above descrip- tion is from a specimen in the writer’s collection, which came from Cambodia. Morelet’s specimens are larger, his type be- ing 173 millimeters in length. CRISTARIA HERCULEA ( Middendorff ). Shell irregularly ovate, somewhat solid, inflated, with a very high, rounded or somewhat biangulate posterior ridge; beaks low but full, sculptured with a number of wide, low ridges running neatly parallel with the hinge line and extending well out on the shell; on the posterior slope there is a row of plications extending from the beaks towards the posterior end and below these folds there is a low, radial ridge; growth lines irregular; epidermis blackish on the body of the shell where it is developed into concentric lamellz or ridges, and smooth and brownish on the earlier growth. There is a very feeble anterior wing and a low dorsal one; pseudocardinals wanting or represented by a mere raised line; laterals, one in 228 CRISTARIA each valve, small and short; beak cavities shallow, with one or two muscle scars; adductor scars shallow ; nacre lurid, pur- plish-white, often blotched. Length 170, height 112, diam. 67 mm. Kast Siberia; Amurland; North China. ? Anodonta herculea Mippenvorrr, Bull. Phys. Math. Ac. St. Pet., VI, 1848, p. 303.—Sib. Reise, II, 1851, p. 278, pl. xx, fig. 5; XXII, figs. 1, 2; xxvi, figs. 1. 2—DersHAyes, Bull. Nouv. Arch. Mus., IX, 1873, p. 1, pl. 1, fig. 1. Anodonta (Dipsas) herculea Cuessin, Conch. Cab. Ano., 1875, p. 575, Dhwik, jee see. Cristaria herculea VON lwERING, Abh. Senck. Nat. Ges., XVIII, 1893, p. 140.—SIMPsSON, Syn., 1900, p. 584. Barbala herculea Pare, Conch. Sam., IIL, 1890, p. 175. Dipsas plicata var. clessint Kovevr, part, Abh. Senck. Nat. Ges., XI, 1879, p. 429, pl. xv. There is a fine specimen of this species in the National Mu- seum collection said to come from Japan. It differs from C. Spatiosa in being shorter, more inflated, and in having a much higher posterior ridge, while the plications of the posterior slope are more strongly developed than in that species. From plicata it differs much in shape, being drawn out to a blunt, rounded posterior point at the median line; it is far more in- flated than that species, and has a higher posterior ridge. Its posterior dorsal outline is somewhat incurved. Craspedodonta smaragdina An’ton, Verz. der Conch., 1839, p. 16, No. 592; Clessin, Conch. Cab. Ano., 1875, p. 93, pl. xxvul, fig. 2; a badly figured little shell, said to come from North America; may be a young C. herculea. CRISTARIA SPATIOSA (Clessin). Shell enormously large, irregularly long ovate, with a slight wing behind, subsolid, somewhat inflated, gaping before and behind, with a full, widely rounded posterior ridge, which is either straight or curved downward in the middle; the out- line of the shell above the posterior slope is incurved and it ends in a wide, feeble biangulation behind ; beaks low, moder- CRISTARIA 229 ately full, their sculpture not observed; surface with irregular growth lines, which become somewhat sulcate around the edge of the shell; epidermis, dark brown or blackish ; hinge line regularly curved, with epidermal matter folded in throughout ; pseudocardinals wanting; in each valve there is a short, im- perfect lateral; beak cavities shallow, with two or more deep scars; nacre dull, white, somewhat thickened in front, some- times showing the posterior dorsal plications, which are more distinct on the outside of the shell; muscle scars shallow. J] cannot say that these shells are dimorphic, but certain speci- mens, which may be males, have a straight posterior ridge, which ends below the median line; in others it is upcurved behind and ends above the median line and these may be females. Length 210, height 115, diam. 73 mm. This is an ordinary sized shell: a larger one measures: length 240, height 120, diam. 70 mm. | Japan. It seems to be abundant in Lake Biwe. Anodon herculeus SowERsy, Conch. Icon., XVII, 1867, pl. 111, he. 7. Anodonta (Dipsas) spatiosa CLesstn, Conch. Cab. Anodonta, ROZ5; (Ps 1799 pl: LVit, fis. -2. Cristaria spatiosa VON IHERING, Abh. Senck. Nat. Ges.. XVIII, 1893. p. 145.—SIMPSON, Syn., 1900, p. 584. Barbala spatiosa PaivrEL, Conch. Sam., III, 1890, p. 175. Dipsas plicata var. japonica Kosrevr, Abh. Senck. Nat. Ges., x FS79, p. 420, ple xLvir. A very large species. which has quite commonly been taken for C. plicata. It is solider and much more elliptical in outline than that species. Subgenus PLETHOLOPHUS Simpson, 1900. Pletholophus StMPsoN, Syn., 1900, p. 585. Shell short-elliptical, lenticular, but little thickened in front, with compressed beaks, which are sculptured with low, wide, concentric ridges, scarcely winged in front or behind, pointed 230 CRISTARIA posteriorly ; epidermis smooth, somewhat rayed; hinge teeth very feeble, often nearly wanting; dorsal scars few; muscle scars faint. Animal unknown. Type, Symphynota discoidea Lea. CRISTARIA DISCOIDEA (Lea). Shell nearly evenly elliptical, not inflated, thin but strong, lenticular; the beaks compressed, their sculpture consisting of feeble concentric ridges; with a low wing behind, which is straight on its dorsal edge ; anterior end evenly rounded, wing- less; base line regularly curved; the shell ends posteriorly in a blunt point at the median line; posterior ridge almost want- ing ; surface nearly smooth, yellowish-green, with a wide, faint, concentric, green band near the edge, the umbonal region pale brownish-green, very feebly rayed throughout; pseudocardi- nals wanting or reduced to mere raised threads, laterals scarce- ly developed, one in each valve; beak cavities shallow, with one or two scars in each; posterior dorsal plications wanting or only shown as mere vestiges; muscle scars shallow, the posterior crescentic ; nacre bluish-white, minutely radially gran- ulous ; iridescent behind. Length go, height 55, diam. 28 mm. Symphynota discoidea Lea, Tr. Am. Phil. Soc., V, 1834, p. 75, pl. Xi; He: 33scObs., Lwle34) p57, Pls neste Barbala discoidea H. and A. ApAms, Gen. Rec. Moll., II, 1858, p. 501.—CHENU, Man., 1859, II, p. 145, fig. 716. Dipsas discoidea Kuster, Conch. Cab. Unio, 1862, p. 306, pl. Chet: Cristaria discoidea SIMPSON, Syn., 1900, p. 585. Margarita (Unio) discoideus Lea, Syn., 1835, p. 47; 1838, p. 28. | Unio discoideus HANEY, Biv. Shells, 1843, p. 214, pl. Xxt, fig. 57. Margaron (Unio) discoideus Lua, Syn., 1852, p. 46; 1870, p. 74- Unio tenuis Gray, Griffith’s Cuv., XII, 1834, p. 601 (index), pl. XXIV, He, 2- CRISTARIA 231 Anodonta chinensis Kuster, Conch. Cab. Ano., 1853, p. 51, pl. Mt ies. Unio magnificus Sowersy, Conch. Icon., XVI, 1867, pl. vu, fig. 280. Anodonta gruneriana CLEssIN, Conch, Cab. Ano., 1875, p. 172, ple Evi ios: -2 4. There are often one or two dark rays on the posterior slope. It is a very neat shell and is sometimes so nearly des- titute of teeth that it is taken for an Anodonta. Gray’s and Lea’s names were published in the same year and I have no means of knowing which appeared first. Var. sauttert Haas. “Differs from typical discoidea by the strongly developed claustra, which are double in the left valve in their prastumbonal as well as in their postumbonal portion.” ( Haas.) Type locality, Lake Candidins, Formosa. Cristaria discoidea sautters Haas, Ann. Mag. Nat. Hist., (8), WE TOL; ip. 409: CRISTARIA PARVULA (Heude). Shell thin, small, long elliptical or obovate, subcompressed, rounded in front, with a small post-dorsal wing, which in well- preserved shells is angled behind ; posterior ridge low, scarcely biangulate; beaks low and subcompressed, their sculpture a few longitudinal bars parallel to the dorsal line; surface with fine concentric growth marks, brownish or olive, rayless; pli- cations of the posterior slope faint; left valve with a single, very faint, long and curved pseudocardinal and one low faint lateral; right valve with two feeble pseudocardinals and a single lateral; muscle scars faint; nacre bluish or purplish, iridescent. Length 58, height 34, diam. 18 mm. Kien-té sud; Canton River, China. Dipsas parvulus Heupe (part), Conch. Fluv. Nank., IV, 1878, pl. x3xir, fel 65. Barbala parvula Paret, Conch. Sam., IIT, 1890, p. 175. Cristaria parvula Simpson, Syn., 1900, p. 585. 232 CRISTARIA I am doubtful whether this is more than a variety of C. discoidea, the specimen figured by Heude being a young shell. I have seen a shell, which I believe is Heude’s species, tha‘ differs from the young of C. discoidea in being darker colored, a little rougher, and duller colored, in having longer, more delicate and more curved pseudocardinals, and a little darker nacre. - All the young of discoidea I have seen are slightly biangulate behind; this is hardly so. CRISTARIA REINIANA von Martens. Shell elliptical or slightly rhomboid, rather thin, subcom- pressed, with a small post-dorsal wing, which is straight above and angular behind; posterior ridge but slightly developed, there being three faint darker ridges; beaks low and com-- pressed, their sculpture consisting of feeble ridges parallel to. the dorsal line; on the posterior slope there are sometimes a few slight plications; color greenish or brownish, sometimes rayed; there is a single rudimentary, linear pseudocardinal in each valve and one slender lateral; plications of the posterior slope scarcely developed; muscle scars shallow; nacre bluish- white. Length 55, height 35, diam. 18 mm. Length of largest National Museum shell 60, height 35, diam. 18 mm. Japan. Cristaria reiniana VON Martens, Jahrb. Mal. Ges., II, 1875, p. 136, pl. 111, fig. 4.—Simpson, Syn., 1900, p. 585. ? Dipsas remniana Konrtr, Abh. Senck. Nat. Ges., XI, 1879,. P.432) pl aa, fies ao ex, pe. Anodonta reiniana von IHERING, Abh. Senck. Nat. Ges... RVI; 1893; p. 147. Barbala reiniana Pater, Conch. Sam., III, 1890, p. 175. Pletholophus reiniana Preston, Rec. Ind. Mus., VII, 1912, p. 281. The species is rather more rhomboid than C. discoidea, to. which it is nearly related. CRISTARIA 233 There are two Cristarias in the National Museum, said to come from Japan, that are a little longer in proportion than the described specimens, and a little more inflated at the pos- terior base, but it is probable that they are females. CRISTARIA CENTILIANA Heude. Shell somewhat elliptical, subsolid, compressed, with low beaks, with two dark, radiating lines on the posterior slope; the dorsal line not so much rounded as the basal one; with a very feebly developed anterior and posterior dorsal wing ; rounded in front; the posterior point blunt and raised above the median line; epidermis black, apparently feebly rayed; right valve with two delicate, lamellar pseudocardinals and one lateral; muscle scars probably shallow ; nacre greenish-purple, iridescent. Length 80, height 50, diam. 20 mm. Ie-Fou-Kien, China. Cristaria gentilianus Uxupr, Conch. Fluv. Nank., VII, 188r1, pl. 11, fig. 08. Cristaria gentiliana Simpson, Syn., 1000, p. 586. Barbala gentiliana Payres, Conch. Sam., III, 1890, p. 175. The epidermis is darker than that of C. discoidea, the nacre is differently colored, the pseudocardinals of the right valve are two in number, while in discoidea there is only one, and the shell is longer in proportion than shells of discoidea of the same size. Younger shells of the latter are often as much elongated as is Heude’s species and I think it more than prob- able that it is only a variety of Lea’s discoidea. CRISTARIA SWINHOEI (H. Adams). Shell rhombic obovate, thin, scarcely inflated, without a de- fined posterior ridge, but with a couple of very faint, dark ridges on the posterior slope; beaks low and compressed, their sculpture not discernible from the specimens examined; an- terior end rounded and apparently without a dorsal wing; posterior dorsal wing moderate, ending behind in an angle; surface with irregular, concentric growth lines, rayless, green- 234 CRISTARIA ish-yellow, sometimes with indistinct, darker, concentric bands ; left valve with a small, lamellar pseudocardinal and one or two blurred, lamellar laterals; right valve with one pseudo- cardinal, with vestiges of one or two above it and a single delicate lateral; beak cavities shallow, with one or two faint scars; muscle scars shallow and indistinct ; nacre bluish-white, somewhat iridescent and having a wide, prismatic border. Length 55, height 34, diam. 20 mm. ‘Tonkin ; Cambodia. Anodonta swinhoei H. ApAms, Proc. Zool. Soc. Lond., 1866, p. 446.—CLEsstn, Conch. Cab. Anodonta, 1876, p. 125, pl. Lkxvy, fo. 0, Anodon swinhoei Sowrersy, Conch. Icon., X V1, 1868, pl. xxvit, he. 108. Cristaria swinhoei SIMVSON, Syn., 1900, p. 586. Pletholophus swinhoet Preston, Rec. Ind. Mus., VII, 1912, p. 281. A species that evidently stands close to C. discoidea and C. gentiliana. It is rather more inflated and elongated than the former, and has more completely developed hinge teeth than either. The laterals of this species are sometimes split up as in Symphynota compressa. CRISTARIA INANGULATA Haas. “Shell short-elliptical, nearly unwinged, rather thin and in- flated, rounded in front and behind. Posterior ridge rounded, low. Basal margin regularly curved. Beaks not prominent, situated at 35/100 of the total length, with low, wide ridges grouped round an apical protuberance, the first ones doubly looped, the following ones becoming slightly undulate. F/pi- dermis greenish-brown, shining, rayed. Hinge consisting of a single, low, lamellar pratumbonal, and a single, low, nearly reduced, postumbonal claustrum in each valve. Anterior cica- trices faint, that of the anterior adductor and that of the an- terior retractor confluent. Posterior cicatrices confluent, faint ; 2-3 dorsal cicatrices lying in a row, often united in a groove, CRISTARTA 2G situated under the beaks. Beak cavities shallow. Nacre red- dish, bluish towards the edge. Length 99, height 59, diam. 39 mm.” (Haas. ) Cristaria inangulata f1Aas, Ann. Mag. Nat. Hist., (8), 1910, WAS sp: 490: CRISTARIA NICOBARICA (Morch). “Shell irregularly oval, slightly convex; lines of growth irregular; the marginal half of the shell olivaceous, with very many obscure, radiating, obsolete, faint green rays. Within silvery, iridescent posteriorly. Umbones anterior, flat, eroded ; dorsal margin slightly curved; anterior margin rounded, nar- rower; ventral margin quite curved in front and behind, slightly incurved in the middle; posterior margin somewhat narrow, bent. Cardinal teeth almost wholly wanting; lateral tooth linear, nearly obsolete.” (Morch.) Type locality, Nicobar Islands. Mytilus nicobaricus Fasricius, Catalogue, 1825, p. 65. Alasmodonta (subg.?) nicobarica Morcu, Jl. de Conch., XX, LOZ2 Day Ge 7: Pseudodon nicobaricus S1MPsON, Syn., 1909, p. 838. “Anodonta sollingeri Mousson (Java, p. 96, t. xvii, f. 1) is similar, but the species of Fabricius differs: in the curved ventral margin, suddenly ascending posteriorly, as well as in the margin of the dorsal slope, which is not at all curved.” (Morch. ) Fabricius gave no description of his J/ytilus nicobaricus, so that the species must be credited to Morch. ‘In the Synopsis I placed this species in Pseudodon in reliance upon Morch’s comparison with P. zollingeri Mss. I have recently been favored with the following note on the species from Dr. F. Haas: “I have been able to obtain the type of this species from Copenhagen and to determine that it is to be referred to the genus Cristaria. There is only a single speci- men known and that has been ground off on the edges, so that the shape has been changed. Nevertheless I consider Cr. nico- barica a good species, related to my C. mangulata.” 236 CRISTARIA Subgenus CrAssitesta Simpson, 1900. Crassitesta SIMPSON, Syn., 1900, p. 586. Shell rather solid, elliptic-rhomboid, with a rounded pos- terior ridge, scarcely winged; beaks full, sculpture not seen; epidermis bright, strongly rayed, with two conspicuous light and three dark rays on the posterior slope; hinge line curved; pseudocardinals and laterals reduced to the merest vestiges ; dorsal scars only one or two in the cavity of the beaks; ad- ductor scars faint; nacre lurid. Type, Cristaria radiata Simpson. CRISTARIA RADIATA Simpson. Shell elliptic rhomboid, rather solid, somewhat inflated, with a full, rounded posterior ridge; anterior wing wanting; posterior wing but slightly developed; beaks full, elevated above the dorsal line, much eroded in the specimens seen, but apparently having somewhat doubly-looped sculpture; surface shining, greenish-yellow with narrow and wide green rays; on the posterior slope there are two distinct, yellowish rays; hinge line evenly curved; only the faintest vestiges of pseudo- cardinals and laterals are developed; beak cavities shallow, with one or two pits; muscle scars shallow ; nacre bluish-white, dull, often blotched, not thickened in front. Length 73, height 45, diam. 28 mm. Kien-té sud, (Ngan-houé), China. Dipsas parvulus HeupeE (part), Conch. Fluv. Nank., VII, 1881, pl. Lu, fig. 96. Cristaria radiata SIMPSON, Syn., 1900, p. 586. I do not know where to place this species, which is so dif- ferent from the other Cristarias that it may not belong to that genus at all. Heude applied the name Dipsas parvulus to two entirely distinct forms. figuring the first on plate xxx of the Conchyliologie Fluviatile Nanking and the present species on plate 1.11, hence I have given the last figured form a new name. I do not think it can be an Anodonta and it may be the type of a distinct genus. LEPIDODESMA 237 Genus LEPIDODESMA Simpson, 1896. Lepidodesma Simpson, Pr. U.S. Nat. Mus., 1896, p. 311. Shell large, thin, inflated, with a high, sharp posterior ridge and a second fainter one above it, making the hinder part widely biangulate; beaks very high and full, their sculpture, which extends over the whole shell, consisting of ridges that follow the growth lines; there are two rows of radiating nodules, one on the middle of the disk, and a stronger one on the post-ridge; ligament very large, wide, covered with con- centric scales ; hinge line arched ; there are two pseudocardinals in the left valve, the anterior elongated, running inwardly across the hinge plate and ending abruptly; a shorter, fainter one stands behind it; with two strong laterals, the inner the higher, its edge reflexed upward, and suddenly truncate be- hind; there is one low, elongated pseudocardinal in the right valve, and one lateral, which is reflexed upward; epidermis folded into the hinge and scaly; a single dorsal scar on the inier side of each hinge plate; muscle scars united, pallial line distinct ; beak cavities large and wide; nacre very dull. Ani- mal unknown. Type, Unio languilati Heude. I,EPIDODESMA LANGUILATI (Heude). Shell large, scarcely subsolid, inflated, subtriangular, with two distinct posterior ridges, which curve down in the middle, the lower the higher, the two marking the limit of a wide, de- cided posterior truncation ; base line nearly straight; posterior slope obliquely truncated; ligament very large, dark brown and covered with crescentic scales: the pit in which it is lodged extends forward under the beaks and is filled with epi- dermal matter: beaks very high and full, their sculpture con- sisting of coarse, doubly-looped and doubly-noduled ridges, the bases of the loops and the nodules occurring on the pos- terior ridges; surface covered with very strong ridges, which follow the growth lines; epidermis greenish in young: shells, ash-colored in old ones ; left valve with two compressed pseudo- 238 LE PIDODESMA cardinals, the anterior the longer, and two short, curved lat- erals, the lower much higher and reflexed upward, the upper deflected downward; right valve with one feeble pseudocardi- nal and a strong, retlexed lateral ; beak cavities deep and wide; dorsal scars in a row under the anterior part of the hinge plate; adductor scars shallow; nacre dirty white, dull pur- plish behind, lusterless. Length 170, height 120, diam. 85 mm. Deep River, Kiang Nan, China. Unio languilati Heupr, J. de Conch., XXII, 1874, p 116; Conch. Fluv. Nank., I, 1875, pl. vit. Lepidodesma langiulati Stmrson, Pr. U. S. Nat. Mus., XVIII, 1896, p. 311. Lepidodisma languilati Simpson, Syn., 1900, p. 587. Cristaria megadesma VON MARTENS, S. B. Nat. Fr., 1875, p. 2; Nov. Conch., [1 V5-1876,-p. 052) ol .eoxexy, head. Barbala megadesma PatreL, Conch. Sam., III, 1890, p. 175. A most remarkable and magnificent Naiad, whose relations are a little in doubt, as nothing is known of its anatomy. The beak sculpture resembles that of Anodonta grandis in its earlier stage and later that of some of the Cristarias. A young and an adult shell are in the National Museum collection, from the author. LEPIDODESMA ALIGER (Heude). Shell very large, irregularly triangular, inflated, with high beaks, whose sculpture has not been observed, with a double posterior ridge, the lower one very strong above, which ends behind in a wide biangulation, the shell being rather squarely truncate posteriorly ; post-dorsal wing high, covered with scat- tered nodules, which extend on to the posterior slope and are often turned to one side; anterior end rounded; base line straight or slightly incurved, rounded up a little behind; sur- face strongly sulcate throughout; ligament partially covered by the wing; no measurements are given by Heude. His fig- ure is 195 mm. in length and 157 in height. China. PILSBRYOCONCHA 239 Unio languillati var. aligerus Heupe, Conch. Fluv. Nank., ITI, 1877, pl. Xvi, fig. 37. Lepidodesma aligera Simrson, Pr. U. S. Nat. Mus., XVIII, LOOO pe all; oy. 1900; py 587- Heude believes this to be a variety of his Unio languilati, but although he gives no description, the figure is so different from the type that [ should think this form worthy of specific rank. ‘The concentric sculpture is much finer than it is in lan- guilati, where it consists of coarse ridges; the posterior ridges are more strongly curved and the pustules are more distinctly developed. Genus PILSBRYOCONCHA Simpson, 1900. Pilsbryoconcha SIMPSON, Syn., 1900, p. 587. Shell elongated, elliptical, compressed, thin, with a low, pos- terior wing, narrow and rounded in front, nearly straight be- low, expanded at the post-basal region, pointed behind. Beaks compressed, sculptured with several coarse. low, irregularly concentric undulations, often slightly doubly looped; surface nearly smooth, shining, yellowish to ashy-brownish, sometimes showing very faint rays; hinge straight or slightly curved, reduced to a mere line, often showing a faint, compressed, smooth tooth in front of the beaks, otherwise edentulous ; nacre brilliant, silvery and iridescent; muscle scars faint. Animal pure milky-white; lobes of the mantle united into two short siphons. Type, Anodonta exrilis Lea. PILSBRYOCONCHA LINGUFORMIS ( Morelet). Shell irregularly obovate or subtrapezoidal,; compressed, rather thin, with a moderate posterior wing, behind, which it is obliquely truncated, with a low, rounded posterior ridge; beaks low, their sculpture consisting of nearly straight ridges, which are almost parallel with the dorsal line; dorsal line somewhat curved; surface sculptured with numerous concen- tric growth lines; epidermis ashy to vellow-brown, shining; 240 PILSBRYOCONCHA hinge edentulous or with the merest vestiges of teeth under the beaks ; beak cavities shallow, with a diagonal row of faint scars; nacre soft and shining, bluish or purplish, iridescent, salmon-colored in the beak cavities. The specimen from the Morelet collection belonging to the National Museum and bearing Morelet’s label Anodonta linqueformis differs quite a little from the figure of the type and is probably a female shell as it is considerably produced in the post-basal region. The figure of the type shows a shorter, higher shell, with no post- basal inflation. Both are bluntly pointed about at the median line. Length of type 105, greatest height 47, diam. 18 mm. Length of Museum, specimen 96, height 52, diam. 20 mm. Siam ; Cambodia. Anodonta linguefornis. MorELET, Ser. Conch., [V, 1875, p. 320, pl. xiv, fig. 5. Margaron (Unio) lingueformis Lia, Syn., 1870, p. 48. Pilsbryoconcha lingueformis SIMPSON, Syn., 1900, p. 587. Morelet’s measurements are of a longer, narrower shell than the one described, his figure being 93 millimeters in length and 55 in height. It may be that this is only a variety of Lea’s Anodonta exilis. PILSBRYOCONCHA SUILLA (von Martens). “Shell oblong, inflated, rather thin, striate; epidermis black- ish-brown; roundly produced in front; higher and more in- flated behind: dorsal margin subconcave anteriorly, poste- riorly from the beaks to the sinulus quite ascending and ob- tusely subalate, thence descending; posterior margin trun- cate, subvertical; ventral margin for the most part straight, horizontal; beaks depressed, with rather strong undulating ridges, conspicuous even when eroded; hinge line in front of the beaks simple, narrow, slightly sinuous and at first sharply descending, then rising, behind the beaks, convex, with a heavy nacreous deposit and towards the sinulus decidedly wider ; PILSBRYOCONCHA 241 sinulus small, obtusely angled; nacre bluish, changing to red towards the beaks: muscular impressions shallow. Long 88; alt. vert. 42.5, alae 61, diam. 36 mm. Beaks at 1-3 of the length.” (von Martens). Type locality, Tonkin. Anodonta suilla von Marrens, Nachr. Deutsch. Mal. Ges., 1902, p. 130. “In profile, it reminds one most of An. lingweformis More- let, which Simpson refers -to Pilsbryoconcha, but it is much more inflated, the beaks are less polished, with strong, irreg- ular, almost ridge-like lines of growth. From An. joudyi Morlet, which was collected by Fruhstorfer in Phuc-Son, An- nam, it is easily distinguished by its straight basal margin and more angulated, projecting anterior margin.” PILSBRYOCONCHA EXILIS (Lea). Shell long obovate, thin, compressed, narrowed and evenly rounded in front, slightly winged behind, the dorsal line straight ; posterior ridge low, widely rounded or feebly bian- gulate, with a shallow radial furrow above it; beaks com- pressed, their sculpture consisting of delicate ridges, which run nearly parallel with the dorsal line; post-basal region con- siderably produced and widely rounded : posterior point rather sharp, mid-way up from the base; growth lines irregular, somewhat sulcate at the outer edge, the posterior slope hav- ing numerous delicate folds, which follow the growth lines: epidermis. pale brown, smooth; hinge a mere line, edentulous or sometimes having a single, low, smooth anterior tooth or prominence in each valve ; beak cavities very shallow, with two or three scars; adductor scars very indistinct: nacre brilliant, richly iridescent. Length 85, height 43, diam. 15 mm. Southeastern Asia, Sumatra, Java. Anodonta exilis Lexa, Tr. Am. Phil. Soc.,VI, 1839, p. 81, pl. Xx, fig. 68; Obs., II, 1838, p. 81, pl. xxu, fig. 68.— Crxs- stn, Conch. Cab. Ano., 1875, p. 171, pl. iv, figs. 6-8. Margarita (Anodonta) exilis Lea, Syn., 1838, p. 32. 242 PILSBRYOCONCHA Anodon evilis CatLow and Reeve, Conch. Nom., 1845, p. 66. Margaron (Anodonta) exilis Lea, Syn., 1852, p. 51; 1870, p. 82. Monocondylea exilis Payret., Conch. Sam., ILI, 1890, p. 174. Pilsbryconcha exilis SIMPSON, Syn., 1900, p. 587. Anodonta siliqua Kuster, Conch. Cab. Ano., 1852, p. 57, pl. XIV, fig. 5. Anodonta polita Mousson, lL. and Suss. Moll. Java, 1849, p. oS, pl xix, figs.<2,.3. Margaron (Anodonta) polita Lua, Syn., 1852, p. 53. Anodon politus Sowrrny, Conch. Icon., XVII, 1867, pl. xu, fig. 36. Monocondylaa compressa Lea, Pr. Ac. N. Sci. Phila., VII, 1863, p. 190; Jly Aer N.: Ser Phila Vil, 1866) p: -30;epiaa, fig. 29; Obs., XI, 1867, p. 34, pl. x1, fig. 29.— CrEssIN, Conch. Cab. Ano.., 1876, p. 258, pl. LXxx, figs. 3, 4. Pseudodon compressa Conran, Am. Jl. Conch., I, 1865, p. 233. Margaron (Monocondylea) compressa Lea, Syn., 1870, p. 73- Spatha compressa PasteL, Conch. Sam., III, 1890, p. 188. Anodon javana SoweRsy, Conch. Icon., XVII, 1867, pl. x1, fig. 33: Anodon gracilis Sowerry? Conch. Icon., XVIT, 1867, pl. x1x, fig. 45. Anodon kelletti Sowersy? Conch. Icon., XVII, 1867, pl. x1x, fig. 71. Anodonta sempervirens DEsSHAYES, Nouv. Arch. de Mus., X, 1874, py 120; pl. Vv, Mes. 45 5. An exceedingly delicate shell, which does not vary remark- ably, yet it has received a large number of names. There is often an especially rich, greenish, iridescent, concentric band near the border inside. PILSBRYOCONCHA EXPRESSA (von Martens). “Shell compressed, elliptic-ovate, well rounded in front, ob- tusely alate behind, posterior margin oblique, ventral margin straight to the middle, roundly expanded posteriorly ; epider- mis concentrically striate, shining; beaks depressed, with un- PILSBRYOCONCHA 243 dulate sculpture, situated at 1-5 (in the young 1-4) of the length ; nacre bluish, towards the beaks lurid yellow. a) Long. 118, alt. vert. 53, ale 69, diam. 27 mm. b) Long. 103, alt. vert. 45, ale 55, diam 22.5 mm. c) Long. 88, alt. vert. 35, ale 47, diam. 18 mm. d) Long. 68, alt. vert. 27, ale 37, diam. 12 mm.” (von Martens). Type locality, Lake Danau-Baru, Indragiri, Sumatra. Anodonta expressa VON Martens, Nachr. Deutsch. Mal. Ges., LQOON Ps F2: “Nearest to 4. exilis Lea from Siam and A. polita Mouss. from Java, but it is easily distinguished in the mature form by the greater height of the posterior half of the shell. The four specimens before me form an age series and show that the proportion of height to length increases noticeably with age; the two younger shells, c and d, remind one very much of A. polita from Java, especially as in c the bright yellow border is also present, but the ventral margin is a ijittle more convex posteriorly and the posterior margin descends more direct from the wing. In the older shells, a and b, this is still more so. In the young shells the surface is somewhat dull, but is polish- ed in the older ones, which are of a dark brown color like the two species referred to.” PILSPBRYOCONCHA CARINIFERA (Conrad). Shell narrow, elliptical, compressed, thin and fragile; an- terior side narrow, rounded at the extremity; posterior side produced, subcuniform, truncated at the extremity ; hinge mar- gin long, straight, elevated, slightly ascending from the ante- rior to the posterior extremity ; beaks not elevated above the dorsal line; basal margin straight in the middle; color of epi- dermis olive-green inferiorly, darker above; hinge margin without a callus. Length 65, height 30, diameter not given. Southeastern Asia, probably. Anodonta carinifera Conrap, Cover of Monography, No. 9, 1837. Pilsbryconcha carinifera Simpson, Syn., 1900, p. 588. 244 PILSBRYOCONCHA The above is Conrad’s description on the cover of the Mon- ography, No. 9. He gives.‘*Rivers of Kentucky, from Mr. John Phillips, who stated that it was from the Ohio or a tribu- tary below Louisville.” No specimen so named can be found in Conrad's collection, but Dr. Pilsbry found an unnamed shell in the Conrad collection, which agrees very well with the above description, which could not have come from Ken- tucky, but which is undoubtedly a Pilsbryoconcha. PILSBRYOCONCHA LEMESLEI ( Morelet). Shell elongated, slightly wider behind and arcuate when old, thin, shining; somewhat compressed, especially posterior- ly, with a low rounded posterior ridge; anterior end rounded ; posterior end with a rounded, somewhat narrowed point 2 short distance above the base; surface irregularly sulcate, light brown, rayless; area of the beaks extensively eroded in the specimen figured, the eroded part being coppery-brown, nacre bluish, iridescent with yellow-brown spots in the center of the shell; hinge edentulous. Length S81, height 32, diam. 14 mm. Cambodia, probably near Battambang, Siam. Anodonta lemeslei More er, Ser. Conch., IV, 1875, p. 328, pl. suv, fig: T. Pilsbryoconcha lemsleyi Simpson, Syn., 1900, p. 588. The type is an old, elongated, rather peculiar shell. Con- rad’s species may be the young of it, and Morelet believes that Marten’s 4. schomburgki is very close to his shell. I have not seen a sufficient amount of material of this genus to determine with certainty whether all these are valid species. PILSERYOCONCHA SCHOMBURGKI (von Martens). “Shell elongate, narrow in front, expanded behind, com- pressed, thin ; epidermis shining, greenish ; dorsal margin near- ly straight, elevated posteriorly into a low, rather long wing: anterior and posterior margins rounded, without distinct an- gles: ventral margin subconcave ; hinge distinctly edentulous ; MEDIONIDUS 245 muscular impressions moderate, anterior accessory impression moderate, subrhomboid ; nacre violaceous red. Length 82, height, at beaks, 27, at posterior end, 38 diam. 15 mm.” (von Martens). Anodonta ( Lamproscapha) schomburgki von Martens, Pr. Zool. Soc. Lond., 1860, p. 15. Pilsbryoconcha schomburgki Simpson, Syn., 1900, p. 588. I know nothing of this species. Von Martens remarks that “the thin and very flat shell and the want of edges at the mar- gins render it impossible to associate this species with Spatha rostrata.” I presume that it should be placed in Pilsbryocon- cha and it is possible that it is synonymous with some one of the other species here described. Genus MEDIONIDUS Simpson, rooo. Medionidus Simpson, Pr. Ac. N. Sci. Phila., 1900, Pp. 77.— Ortmann, Ann. Car. Mus., VIII, 1912, p. 334. Shell elongated, rather inflated, often arcuate when adult, generally having a posterior ridge; dorsal slope and occasion- ally the posterior portion of the shell plicately or nodulously wrinkled : epidermis smooth and bright, variegated with brok- en green rays and blotches; beak sculpture consisting of rather fine, subparallel, often broken ridges in two loops, the anterior rounded, the posterior somewhat angled, occasionally broken up into zigzags ; pseudocardinals small, stumpy, and somewhat roughened: laterals rather short, slightly curved and club- shaped, remote; dorsal cicatrices few, placed under the hinge just behind the beaks ; anterior cicatrices rather deep; posterior cicatrices rounded, large, and well impressed: anterior part of shell somewhat thickened; female shell slightly swollen just behind the middle of the base. Animal having inner gills wholly or in part free from the abdominal sac; marsupium occupying the central posterior part of the outer gills, sometimes extending nearly their whole length, consisting of few to many rather large, irregular ovi- 246 MEDIONIDUS sacs, which are not so distinctly marked out as in Lampsilis. but which have rounded bases; mantle much thickened on its lower edge, which is dark colored and sometimes papillous. Type, Unio conradicus Lea. This genus contains a few rather closely related species which are found in the Tennessee, Alabama and Chattahoochee river systems and southeast to the Suwanee River, Florida. It is closely related to Lampsilis, but the embryos are contained in irregular, though distinctly marked, ovisacs near the center of the outer gills instead of in regular ovisacs at the hinder part of the gills. The marsupial swelling of the female shell is less developed than in L.ampysilis and is placed farther for- ward than in that genus. The male shell is generally somewhat arcuate and the species generally have a well-developed pos- terior ridge, characters not often found in Lampsilis. Key TO SPECIES OF MEDIONIDUS. Shell without a posterior ridge. M. conradicus. With a posterior ridge. Marked with undulating or broken rays. Solid. M. king. Subsolid or thin. M. parvulus, penicillatus, simpsonianus, acutissimus. Without rays. M. walkers. Group of Medionidus conradicus. Shell small, usually with a well-defined posterior ridge; pos- terior end and sometimes the greater part of the shell slightly wrinkled or nodulous; epidermis rather smooth, painted with rays broken into irregular arrow-head markings or blotches ; pseudocardinals rather small and imperfectly developed; lat- erals of left valve separated by a narrow, shallow furrow ; nacre greenish, purplish, or bluish. The male shell is often decidedly arcuate; that of the female is swollen at or behind the center of the base. Animal having the character of the genus. MEDIONIDUS 247 MEDIONIDUS ConRADICUS (Lea). Shell rather small, long elliptical, usually arcuate, especially when fully adult, subinflated, subsolid, inequilateral, rounded in front, with a low, sometimes scarcely developed, posterior ridge ending in a rounded point at the posterior base; beaks only slightly inflated, but little elevated, sculptured with fine, irregular corrugated ridges, which have a tendency to fall into two loops; posterior end, especially the dorsal slope, generally more or less wrinkled, sometimes the anterior half of the shell shows slight corrugation; epidermis scarcely shining, tawny to yellowish-green, with feeble. broken, wavy darker rays, which sometimes show a tendency to break into blotches or arrow-head markings; left valve with two stumpy pseudocard- inals and two laterals; right valve with one pseudocardinal and one lateral; anterior scars deep; posterior scars shallow: beak cavities but slightly excavated ; nacre bluish to dirty flesh- color. The male shell is generally considerably arcuate and is often wider behind; that of the female 1s a little produced along the middle of the base, and this part of the shell is sometimes faintly, radially grooved. It is considerably thick- ened in front. Length (male) 55, height 25, diam. 16 mm. Length (female) 42, height 18, diam. 14 mm. Tennessee River drainage; Cahawba River, Alabama, and probably the entire Alabama River system. Type locality unknown. Unio conradicus Lea, Tr. Am. Phil. Soc., VI, p. 63, pl. 1x, fig. 23; Obs., I, 1834, p. 175, pl. 1x, fig. 23 —Han ey, Biv. Shells, 1843, p. 176, pl. xxi, 22.—Kuster, Conch. Cab., Unio, 1861, p. 179, pl. Lv1, fig. 5—Sowerrsy, Conch. Icon., XVI, TS60, ple. Liv; ps 278: Margarita (Unio) conradicus Lea, Syn., 1836, p. 13; 1838, pai: Margaron (Unio) conradicus Lea, Syn., 1852, p. 21. Medionidus conradicus Stimpson, Syn., 1900, p. 589.—ORrT- MANN, Ann. Car. Mus., VIII, 1912, p. 335, fig. 22. 248 MEDIONIDUS Unio conradius Conrap, Monog., X, 1838, p. 87, pl. xivi, fig. 3. Margaron (Unio) conradianus L&A, Syn., 1870, p. 32. Unio conradianus B. H. Wricut, Check List, 1888. Very closely allied to the following, but it has a smoother shell, a less developed posterior ridge and is more rounded posteriorly. MEDIONIDUS PARVULUS (Lea). Shell small, elongated, subcompressed, subsolid, somewhat rhomboid, with a low. rounded posterior ridge, above which it is corrugately plicate; in front of it the surface is smooth; beaks moderate, their sculpture not seen; surface greenish or yellowish, marked with delicate, green, undulating or zigzag lines, which sometimes form very faint rays; pseudocardinals small and with the laterals much as are those of the other species of the group; nacre bluish-green. Length 40, height 20, diam. 11 mm. Coosa River, Alabama; Chattanooga and Swamp creeks, northwest Georgia. Type locality, Coosa River, Ala.; Chattanooga, Georgia. Unio parvulus Lea, Pr. Ac. N. Sci. Phila., TV, 1860, p. 307; Jl. Ac. N. Sci. Phila., VI, 1866, p. 45, pl. Xv1, fig. 43; Obs., M1 2867; p40. ply XVI, ne. 43: Margaron (Unio) parvulus Lea, Syn., 1870, p. 32. Medionidus parvulus SIMPSON, Syn., 1900, Pp. 590. A doubtful species, but T can hardly connect it with any of the others. It may be a variety of the conradicus, but it is smoother, differently colored and more delicate. All the shells I have seen are females and are slightly produced near the center of the base. The posterior point is somewhat raised above the basal line. MEDIONIDUS PENICILLATUS (Lea). Shell small, long rhomboid, subinflated, subsolid, inequilat- eral; beaks scarcely elevated, their sculpture ‘not seen; poste- rior ridge moderately developed, rounded in the adult state, MEDIONIDUS 249 sometimes angular in the young shell; epidermis rather smooth and shining, yellowish to greenish, showing faint darker rays, which are more or less broken and are made up of looped or zigzag lines; posterior slope quite strongly corrugated; left valve with two short, stumpy pseudocardinals and two delicate laterals; right valve with one pseudocardinal and one lateral ; nacre purplish or greenish, often lurid and spotted. The male shell is slightly arcuate and nearly straight on the base line; that of the female is somewhat more fully developed ventrally. Length (male) 40, height 22, diam. 13 mm. Length (female) 28, height 15, diam. to mm. Chattahoochee and Flint Rivers, Georgia. Type locality, Chattahoochee River, Columbus; Atlanta; Flint River, Albany, Georgia. Unio pemcillatus Lea, Pr. Ac. N. Sci. Phila., IX, 1857, p. 171; die teeINe el Phila IN. TSs50. p..203, ph xxi, fig. Ss. Obs. a Val 1350, p. 20, pl: xxi, fie. Ss. Margaron (Unio) penicillatus Tass, Syn., 1870, p. 32. Medionidus penicillatus SIMPSON, Syn., 1900, p. 590. This species has a rather shorter shell than any other mem- ber of the group. It is smoother than conradicus and is less arcuate and has a lower posterior ridge than acutissimus. MEDIONIDUS SIMPSONIANUS Walker. “Shell small, rather thin, somewhat inflated, elliptical, ine- quilateral, strongly plicate on the posterior slope. Epidermis dark yellow, smooth, polished, covered with dark green pen- cilled rays, which tend to break into a network of angular lines covering the entire surface. Anterior end compressed, rounded, and slightly elevated above the line of the hinge superiorly ; posterior extremity obtusely rounded, the tip nearly on the median line of the shell; posterior ridge somewhat angled ; dorsal slope covered with strong, subconcentric, some- what irregular ridges extending from the posterior ridge to the margin; basal margin regularly curved; hinge margin nearly straight, slightly angled between the cardinal and lateral teeth. 250 MEDIONIDUS Cardinal teeth crenulate, erect, rather compressed, those in the left valve nearly on the same line; lateral teeth slender, straight and nearly smooth. Anterior cicatrices well impressed, pos- terior cicatrices distinct, dorsal cicatrices under the plate behind the cardinal teeth. Beak cavity rather shallow, cavity of the shell deep and uniform. Nacre bluish-white, rather thicker anteriorly. Length 36, height 19, diam. 13 mm.” (Walker). Type locality, Calvary, Georgia. Medionidus simpsonianus WaAtkKer, Naut., 1905, XVIII, p. 136, pl. rx, figs. 4-5. “This species belongs to the conradicus group of Medionidus as defined by Simpson, and is most nearly related to M. pen- icillatus. But it differs decidedly from all the described spe- cies in the compression of the anterior end, the elevation of the superior-anterior margin and the regularly rounded pos- terior margin, which is equally curved above and below, the tip being on the median line and not depressed towards the basal margin as in all the allied species. The ridges on the posterior slope are quite strong, but not so numerous as in M. kingi.”’ MEDIONIDUS KINGI (B. H. Wright). Shell small, elongate, solid and somewhat inflated, with a well-developed posterior ridge, which is bluntly angled or rounded, with rather full, high beaks, whose sculpture con- sists apparently of slightly doubly-looped ridges; posterior slope having strong, curved, radial ribs; there are sometimes a few slight corrugations on the body of the shell; surface hardly shining, tawny, with feeble, broken, dark rays, which are often split up into wavy, irregular hair lines ; pseudocardi- nals small, solid, triangular, two in the left valve and one in the right; there are two slender laterals in the left valve and one in the right; anterior scars well marked; posterior scars shallow; nacre lurid purple, iridescent behind. The male shell is somewhat arcuate, its rounded posterior point being MEDIONIDUS 250 at the base of the shell; in the female shell, which is smaller, the posterior point is considerably elevated above the base and the marsupial area is decidedly swollen. Length (male) 45, height 23, diam. 16 mm. Length (female) 36, height 18, diam. 15 mm. Type locality, branch of Flint River, Baker County, Georgia. Unio kingi B. H. Wricut, Nautilus, XII, 1900, p. 139. Medionidus kingi StMPsoN, Syn., 1900, p. 590. This species is more solid than any member of the group. It is considerably inflated, and has a more tawny epidermis than any of the others. MEDIONIDUS ACUTISSIMUS (Lea). Shell small, subinflated, rhomboid, with a high, sharp, some- times slightly double posterior ridge; beaks rather prominent, their sculpture not observed; posterior slope and sometimes the greater part of the shell corrugately folded; surface shin- ing, yellowish or greenish, marked with faint rays composed of zigzag or broken lines; left valve with two stumpy pseudo- cardinals and two laterals; right valve with one pseudocardinal and one lateral, nacre salmon, flesh-color or whitish, pur- ple or reddish. Male shell arcuate, the hinder end drawn down to a sharp point at the posterior base; in the female shell this point is elevated a little above the base line and the middle of the base is swollen. Iength (male) 45, height 20, diam. 18 mm. Length (female) 35, height 17, diam. 13 mm. Alabama River system. Type locality, Alabama River. Unio acutissimus Lea, Tr. Am. Phil. Soc., IV, 1831, p. 80, pl. x, fig. 18; Obs., I, 1834, p. 99, pl. x, fig. 18.—Conrap, Mon- og., X, 1838, p. 86, pl. xivu, fig. 2—Hantey, Biv. Shells, 1843, p. 177, pl. xx, fig. 35.—CHENU, II]. Conch., 1858, pl. vul, figs. 3, 3a, 3b.—Sowersy, Conch. Icon., XVI, 1866, pl. XXXVI, fig. 189. Margarita (Unio) acutissimus Lea, Syn., 1836, p. 14; 1838, p. 14. 252 MEDIONIDUS Margaron (Unio) acutissimus Lua, Syn., 1852, p. 21; 1870, De.<32. ‘ Medionidus acutissimus Simpson, Syn., 1900, p. 590. Unio semiplicatus Kuster, Conch. Cab. Unio, 1862, p. 279. pl. xciv, fig. 4. Umo rubellinus Lea, Pr. Ac. N. Sci. Phila., IX, 1857, p. 32; ih Acainy Sci. Phila., IV, 1858, p. 70, pl. x1, fig. 51; Obs., VEi1858, p.-70, pl. xi dic. Bik Margaron (Unio) rubellinus Lawa, Syn., 1870, p. 32. Unio rubelianus Sowerpy, Conch. Icon., XVI, 1868, pl. xc, fig. 490. Lea’s Unio acutissimus seems to be merely a young and somewhat compressed form of rubellinus, which is adult and considerably inflated. The species of this group are close and often difficult to satisfactorily determine. This form is more inflated and has a higher, sharper posterior ridge than any of the rest, and the male is more decidedly arcuate. There is a Unio semiplicatus of Troschel in Wiegman’s Archiv. for 1841, p. 180, but I do not know what it 1s. Kuster credits his species to Australia, but it is evidently Lea’s shell, no such species being found in Australia Group of Medionidus walkert. Shell rather short, inflated, with a high posterior ridge; pos- terior slope strongly corrugated: epidermis dark, — slightly clouded; nacre reddish or greenish. MeEDIONIDUS WALKERI (B. H. Wright). Shell subrhomboid, rather short, solid, slightly inflated, with a high, angled posterior ridge; beaks full, moderately high, their sculpture not observed ; posterior slope covered with radi- ating, curved corrugations; the remainder of the shell with strong, irregular growth lines, sometimes feebly corrugated ; epidermis dark, apparently unicolored, but when viewed by transmitted light it is often clouded or spotted, sometimes having a few angular, dark spots, but never rayed; left valve NEPHRONAIAS 253 with two somewhat compressed, but solid, pseudocardinals and two small laterals; right valve with one pseudocardinal and one lateral; nacre reddish or greenish, iridescent behind, much thickened in front. The male shell is decidedly rhom- boid, being straight on the base, bluntly pointed at the poste- rior basal part, and obliquely subtruncate on the posterior slope. The female shell is considerably swollen just behind the central base and has the posterior point raised above the base line. The female shell is smaller than that of the male. Length (male) 42, height 23, diam. 16 mm. Length (female) 36, height 22, diam. 14 mm. Type locality, Suwanee River, Madison Co., Florida. Also Ochlocknee River, Georgia. Umo walker B. H. Waicu'r, Naut., XI, 1897, p. ot. Medionidus walkeri Stmpson, Pr. Ac. N. Sci. Phila., IQOO, p. 77 plat, Ase 55) Syn., 1900, Pp. 5O1. Quite distinct from the other species of the genus, as it has a high, well-defined posterior ridge and a dark, rayless epider- mis, which, when fresh, is almost cloth-like. Genus NEPHRONAITAS Fischer and Crosse, 1893. Nephronaias Fiscurr and Crosse, Miss. Sci., I1, 1893, p. 556. Nephronajas Ortmann, Ann. Car. Mus., VIII, 1912, p. 324. Shell elliptical, biangulate behind, that of the male showing a tendency to become arcuate with age, the female usually having a posterior inflation and never arcuate; surface con- centrically sculptured; beaks low, with faint, broken ridges, which show a tendency to fall into two rounded loops ; pseudo- cardinals generally rather compressed, ragged; laterals ob- liquely ridged; cavity of the beaks rather deep, dorsal muscle scars distinct, running in a line from the beak cavity downward and forward. Animal having the branchie rounded below, outer the larger behind, inner the larger anteriorly, free from the abdominal sac for all or part of their length; mantle thick- 254 NEPHRONATAS ened on the edge, which is often dark colored; anal and bran- chial openings large and well furnished with papillae. Noth- ing is known of the marsupium of any members of this group, the animals examined probably being males; but it is most likely that when gravid the ovules will be found in distinctly marked ovisacs in the posterior part of the outer gill, some- thing as in Lampsilis. Type, Unio plicatulus Charpentier. The genus Nephronaias, as diagnosed in the Synopsis and the present work, consists of some twenty or more species belonging to Mexico and Central America, with two or three species extending into the isthmian part of Colombia and possibly one or two reaching extreme southern Texas. I regret that I have not been able to examine gravid females of any of the species, but I am fully convinced that while the group has some characters allying it to Unio, such as the biang- ulation of the posterior end, there generally being a distinct, double posterior ridge, and the arcuation of many old male shells, yet it is most closely related to Lampsilis. I have been fortunate enough to examine shells of nearly all the species and these with the figures of Sowerby, Kuster, Fischer and Crosse and von Martens have shown me that in nearly every species the shells are distinctly dimorphic. That of the male is either incurved, straight, or very slightly rounded out on the base with the angle of the lower posterior ridge on the base line, while that of the female has a more or less decided marsupial swelling, is never arcuate, and has the lower point of the posterior ridge above the base line. It seems to me that all the authors, who have written on the Naiades of this region have either totally failed to note that a majority of them have shells of two forms or have not given the fact sufficient weight, and in several cases the male shell has received one name and the female another—as is the case in [,ampsilis and Truncilla. In some of the species, notably U. gundlachi and medellinus, the marsupial swelling NEPHRONATAS 255 of the female is as greatly developed as in any species of Lampsilis. Ina few instances where I have been able to exam- ine only a single form of a species I could not be positive whether it should be placed here or in Unio. ‘The whole group is a difficult one and I have found great variation of specimens among the species and comparatively few shells that at all perfectly agree with the published figures or descriptions. Group of Nephronaias medellina. Shell scarcely sulcate, shining, rather brightly rayed, dis- tinctly biangulate behind, solid, swollen; beaks rather full, with delicate sculpture; pseudocardinals solid, stumpy, tri- gonal; laterals heavy, somewhat club-shaped; nacre rich and soft, silvery or purple; female shell considerably inflated at the post-basal region, and differing somewhat from that of the male. NEPHRONAIAS MEDELLINA (Lea). Shell long-rhomboid, solid, subinflated, with a rather high, rounded posterior ridge, which is slightly double below and ends in a wide subtruncation; posterior slope obliquely trun- cate; beaks only moderately full and high, their sculpture not observed ; posterior slope often having slight plications or cor- rugations, the rest of the shell nearly smooth. Surface green- ish, darker above, with faint, somewhat wavy, wide or narrow rays; left valve with two strong, ragged pseudocardinals and one strong lateral; right valve with one pseudocardinal and a small tooth in front of and another behind it, and one lateral : sometimes the laterals are more or less subdivided; beak cav- ities shallow; muscle scars smooth, not deep; nacre purple, reddish or salmon. ‘The female shell is somewhat inflated at the post-basal part ; the male shell is slightly arcuate. Length 70, height 39, diam. 25 mm. State of Vera Cruz, Mexico. ? Unio purpuriatus Say, New Harm. Diss., (newspaper form), January 15, 1831. 256 NEPIHRONATAS Unio medellinus Lea, Tr. Am. Phil. Soc., VI, 1838, p. 39, pl. xu, fig. 34; Obs., II, 1838, p. 39, pl. xu, fig. 34.—Hantey, Biv. Shells, 1843, p. 193, pl. xx1, fig. 19; pl. xxi, fig. 8— CHENU, Ill. Conch., 1858, pl. xvu, figs. 6, 6a, 6b—Kusterr, Conch. Cab., 1861, p. 162, pl. xvi, fig. 5—Sowrrsy, Conch. Icon., XVI, 1866, pl. xxxur, fig. 171.—von Martens, Biol. Cent. Amer., Moll., 1901, p. 517, pl. xxxrx, figs. 7-7b. Margarita (Unio) medellinus, Lira, Syn., 1836, p. 26; 1838, p. 10. Margaron (Unio) medellinus Lea, Syn., 1852, p. 29; 1870, p. 45. Nephronias medellmus Simpson, Syn., 1900, p. 592. Umo strebeli Lea, Pr. Ac. N. Sci. Phila., X, 1866, p. 133; jl. Ac. N. Sei.-Phila., VI, 1868, p.-318, pl: 11; fig, 137; Obs. ALD, 1660; p.778;. pl. 1a, Agrees tk. Margaron (Umo) strebeli Lea, Syn., 1870, p. 53. Lampsilis strebeli PirsBry, Pr. Ac. Nat. Sci. Phila., 1909, p. 533: Unio aztecorum strebeli von Marrens, Biol. Cent. Amer., Moll., 1900, p. 503, pl. XXXvII, figs. I-2a. The type of Unio medellinus is a female shell, most decid- edly produced at the posterior base, and having the outline and much the appearance of a female Lampsilis radiata. The type of Unio strebeli from Dr. Strebel is in the National Mu- seum collection and is probably a male, though it is very slightly produced in the post-basal region. With it there is another shell from Dr. Strebel from Vera Cruz, the type local- ity, which, though younger than the type, has a most decided marsupial swelling. The Unio purpuriatus of Say was believed by Conrad to be the same as Lea’s medellinus, but Fischer and Crosse in the Mission Scientifique doubt it. As Say never figured his ‘species and as his type is not known to be in existence, [ think it is best to use Lea’s name. Pilsbrv, (1. c.). considers the strebeli of Lea specifically dis- tinct from both medellina and aztecorum. NEPHRONAIAS 257 NEPHRONAIAS SAPOTALENSIS (Lea). Shell irregularly long elliptical or slightly rhomboid, solid, inflated, the diameter being greatest one-third of the way from the posterior end; beaks low, their sculpture eroded in the specimens examined; surface smooth, shining, greenish-yel- low with numerous split-up, wavy, elegant rays; left valve with two stumpy pseudocardinals and two strong laterals; right valve with one pseudocardinal and one lateral: beak cav- ities not deep; anterior scars well marked; posterior scars shallow ; nacre brilliant silvery, iridescent behind. Length 56, height 36, diam. 23 mm. Sapotal River, Vera Cruz, Mexico. Umi sapotalensis Lea, Pr. Am. Phil. Soc., II, 1841, p. 30; Tr. cme Pll, S06, VEE, 1842) .p. 233, ply Kxt, fie, 47> 'Obs., III, 1842, p. 71, pl. xx1, fig. 47——Cuenu, Ill. Conch., 1858, pl. xxxin, figs. 4, 4a, 4b.—Sowrrsy, Conch. Icon., XVI, 1868, pl. xi, fig. 495.—FiscHEerR and Crosser, Miss. Sci., Il; 2894,)p. GOT, UXvit; figs. 2; 2a. Margaron (Unio) sapotalensis Lua, Syn., 1852, p. 29; 1870, P. 45. Nephronaias sapotalensis Stmrson, Syn., 1900, p. 592. Nephronajas sapotalensis OR1MANN, Ann. Car. Mus., VIII, HON, Pie326,.. 19" 2k I have only seen two shells of this species, both of which are probably females, one being considerably and the other strongly produced at the post-basal region. The species seems to be closely related to N. medellina, but is shorter, more in- flated, more brilliantly painted, and its greatest diameter is nearer the posterior end than it is in that form. NEPHRONATIAS COMPUTATA (Crosse and Fischer). “Shell slightly inequilateral, oval-elliptic, rather thick, heavy, a little inflated; epidermis smooth, shining, yellow, with narrow, greenish rays, slightly separated, but becoming closer posteriorly ; anterior margin rounded; posterior margin obliquely subtruncate ; basal margin curved, not sinuate; dor- sal margin slightly curved before and behind the beaks; beaks 258 NEPHRONATIAS not prominent and much eroded. Nacre white. Hinge heavy- Right valve with two unequal pseudocardinals, (the upper compressed, small; the lower trigonal, thick, grooved), and one lateral comparatively short, slightly curved. Left valve with two pseudocardinals, the anterior oblique, quite thick, pro- jecting, grooved, the posterior large, prominent, grooved and two lamelliform laterals. Cicatrices of the anterior adductor muscles deep, grooved ; those of the posterior adductors super- ficial. Ligament brown. Length 77, height 52, diam. 30 mm.” (C. & F.) Type locality, Goatzalcoalcos, State of Vera Cruz, Mexico. Unio computatus Crosse and Fiscurr, Jl. de Con., 1893, XLI, p. 295.—FiscHer and Crosse, Miss. Sci. Mex., Moll., I, 1894, p. 601, pl. Lxvil, figs. 2, 2a. “By its ornamentation, U..computatus resembles U. sapotal- ensis Lea; but that species, of smaller size, is relatively thick- er, more inflated, especially in the middle, and the cardinal tooth in the left valve is very heavy. The shells of U. com- putatus of the same size are thin and the hinge delicate.” This species was accidentally omitted in making up the Synopsis. Group of Nephronaias azveryi. Shell triangular-ovate, bluntly pointed in front and biangu- late behind, considerably inflated, irregularly sulcate ; umbonal region moderately developed; beaks sculptured with fine, ir- regular ridges, which have a tendency to fall into two rounded loops; pseudocardinals slightly compressed, ragged; laterals having feeble, oblique striation; front part of the shell some- what thickened; posterior part thinner: nacre dull, whitish. Animal unknown. NEPHRONAIAS AVERYI (Lea). Shell elliptic rhomboid, inflated, very solid, with a moder- ate, double posterior ridge ending in a slight biangulation behind, bluntly pointed in front midway up from the base; beaks rather high and full, badly eroded in the only shells seen; surface somewhat concentrically sulcate, scarcely shin- NEPHRONAIAS 259 ing, tawny, rayless; left valve with two heavy, torn pseudo- cardinals, the posterior one more or less split into denticles behind, and having one strong lateral; right valve with one pseudocardinal, a few denticles behind it and a low, wide lat- eral; beak cavities moderate; muscle scars impressed, the an- terior ones rough; nacre buff-colored. The pallial line has faint radial pittings. Length 60, height 43, diam. 27 mm. Isthmus of Darien. Unto averyi Lea, Pr. Ac. N. Sci. Phila., III, TS SOs py 25k JL. Ac. N. Sci. Phila., IV, 1860, p. 269, pl. xiv, fig. 149; Obs., VII, 1860, p. 87, pl. xiv, fig. 140. Margaron (Umo) averyi Lea, Syn., 1870, p. 36. Nephronaias averyi Stmpson, Syn., 1900, p. 593. 3oth shells in the Lea collection, the only ones I have seen belonging to the species, are probably males and have a straight basal line. There is a faint secondary upper lateral in the left valve. The shell is very solid. NEPHRONAIAS CALDWELLII (Lea). Shell irregularly elliptical, subinflated, scarcely subsolid, with a feeble, double posterior ridge; beaks rather full and high, turned forward over a small lunule, their sculpture fine, irregular ridges slightly doubly looped and gradually passing into that on the body of the shell; surface concentrically sculp- tured; epidermis olive-colored; left valve with two ragged pseudocardinals and two laterals, the upper feeble; right valve with one pseudocardinal and a few denticles behind it, with one lateral; anterior scars rough; nacre bluish, dull colored. Length 43. height 29, diam. 18 mm. Isthmus of Darien. Umio caldwellu Lea, Pr. Ac. N. Sci. Phila., II, 1858, p. 118; iiac, No Scere Ehila, 1V,-1860,0p./ 265, ‘pl. xin, fig. 145; Obs., VII, 1860, p. 83, pl. xii, fig. 145.—SoweERBy, Conch. con; XV 1868;\pl. uxxxix) fie: 477. Margaron (Unio) caldwellii La, Syn., 1870, p. 35. Nephronatas caldwellii Simpson, Syn., 1900, p. 593. 260 NEPHRONATAS This may be a young averyi and it has about the same out- lines as that species has at a corresponding size. It is a very much thinner shell and is differently colored within and with- out. It shows traces of faint, bluish-green rays at the posterior end. Group of Nephronaias macnielit. Shell solid, slightly sulcate, biangulate behind, covered with a dull, olivaceous epidermis and having faint, bluish-green rays; beaks rather full, sculpture feeble, consisting of slightly outlined ridges, which are somewhat doubly looped, the looped lines becoming swollen or nodulous at their bases ; pseudocar- dinals compressed and ragged; laterals obliquely striated ; nacre bluish-white, very soft and brilliant, somewhat irides- cent posteriorly ; male and female shells differing but slightly. Animal unknown. NEPHRONAIAS MACNIELII (Lea). Shell irregularly long elliptical, scarcely subsolid, subcom- pressed, with a well-developed, double posterior ridge, which ends in a more or less distinctly marked biangulation ; beaks moderately elevated but not inflated, turned forward over a small lunule; their sculpture consisting of rather fine, double loops, the loops being but slightly connected together ; anterior a little narrowed and rounded; surface irregularly, concentri- cally striated, brownish or tawny green, sometimes having a few faint, green rays; left valve with two radical pseudocardi- nals and two laterals; right valve with one pseudocardinal sometimes slightly split into denticles and one lateral; anterior cicatrices impressed ; nacre bluish. The male shell is nearly or quite straight on the base, while that of the female is slightly produced in the post-basal region. Length 60, height 35, diam. 18 mm. Nicaragua. Unio macnielii Lea, Pr. Ac. N. Sci. Phila., XIII, 1869, p. 124; Jl. Ac. Nat. Sci. Phila., 1874, p. 25, pl. vi, fig. 22; Obs., XID, 1874, p.-29,-pl. vity) figs 2e: Nephronaias macnielti SIMPSON, Syn., 1900, p. 593. NEPHRONAiAS 261 Rather compressed and decidedly biangulate behind. The shell is nearly smooth, and sometimes has a slightly silky ap- pearance when fresh. NEPHRONAIAS OREGONENSIS (Lea). Shell irregularly obovate or elliptical, subinflated, subsolid, with a moderate posterior ridge; beaks not high or full, their sculpture not observed; surface slightly sulcate, dull yellow- ish-green with a few faint, rather narrow rays; left valve with two subcompressed, ragged pseudocardinals and two strong laterals ; right valve with two pseudocardinals, the upper small- er, the two separated by a parallel sided socket and one lateral ; muscle scars well impressed; nacre bluish-white, scarcely shining. ‘The male shell is slightly rounded on the base; that of the female has a decided marsupial swelling. Both shells are feebly biangulate behind, the biangulation in the female being considerably elevated above the base. Length 55, height 32, diam. 20 mm. Nicaragua ; Guatemala. Unio oregonensts Lea, Pr. Am. Phil. Soc., V, 1852, p. 252; Tr. Pirie SOe:, Oc.) 1852p. 275, pl, xxi, hie. 33; Obs., V, 1852, p. 31, pl. xxl, fig. 33—Muscrave, Phot. Conch., 1863, pl. m1, fig. 5—Sowerrsy, Conch. Icon., XVI, 1868, pl. Lxxiv, fig. 383. Margaron (Unio) oregonensis Lea, Syn., 1852, p. 29; 1870, Pp. 45. Nephronaias oregonensis SIMPSON, Syn., 1900, p. 594. Unio radiatulus von Martens, Biol. Cent. Am., Moll., 1900, PSS, pl xXxxix figs..8, a, 0: Very closely related to N. goascoranensis, macnielu, and rowellii, and certain specimens can hardly be assigned to their species. All the specimens I have seen of this species are somewhat rayed, they are not quite so smooth nor so wide behind as macnielii nor so inflated as fully adult rowelli. A careful comparison of von Martens’ figures and descrip- tion of his Unio radiatulus convinces me that it is the same as Lea’s oregonensis. ‘There is a considerable number of spec- 262 NEPHRONAIAS mens of this species in the National Museum collection fron Nicaragua without specified locality. The type of oregonen- sis is somewhat larger than von Martens’ specimen, but there are shells that almost exactly agree with his in size and form. The rays are not shown anything like so clearly in Lea’s figure as they should be. NEPHRONAIAS CHAMPION\ (von Martens). Shell small, compressed, oblong elliptical, densely inequally striate, subsolid, with a mwuderate, somewhat double posterior ridge ending in a slight biangulation behind; beaks slightly elevated, placed rather near the anterior end, their sculpture not observed ; epidermis fuscous, pale and obscurely radiate in the region of the beaks; pseudocardinals subcompressed ; nacre bluish. The small shell figured is probably a young female, as it is rather full at the post-basal region. Length 30, height 17, diam. 6.5 mm. West Guatemala; Paso Antonio, in the Pacific coast region. Unio championi von Marrens, Biol. Cent. Am., Moll., 1900, p. 508, pl. xxxvull, figs. 9, Qa. . I cannot tell much about this species as the description is in Latin and the figure is not very clear. [ rather incline to believe it an immature female Nephronaias, and it would seem to be near oregonensis or macnielu, but from the description it appears to be more strongly sulcate than either. NEPHRONAIAS ROWELLIIL (Lea). Shell subtriangular or subelliptical, pointed behind and bluntly pointed in front; dorsal and basal lines curved, the dorsal more strongly so; posterior ridge well developed, round- ed or sometimes faintly and narrowly biangulate ; beaks rather high, moderately full, their sculpture consisting of fine, doubly looped ridges, which are often slightly nodulous at the bases of the loops; surface somewhat concentrically sulcate ; epi- dermis olive, feebly rayed in the young shells; left valve with NEPHRONAIAS 263 two very ragged, somewhat irregular, subcompressed pseudo- cardinals and two curved laterals ; right valve with one pseudo- cardinal and a faint tooth above it, with one lateral ; beak cav- ities rather deep; muscle scars impressed; nacre bluish-white. Female shell full at the posterior base and rather blunt be- hind: that of the male scarcely, if at all, inflated at the poste- rior base. Length 75, height 47, diam. 32 mm. Nicaragua; Guatemala; Chagres River, Colombia. Unio rowellii Lua, Pr. Ac. N. Sci. Phila., III, 1859, p. 153; Jl Ac. N. Sci. Phila., IV, 1860, p. 256, pl. xu, fig. 136; Obs., VII, p. 74, pl. xu, fig. 136.—SOWERBY, Conch. Icon., XVI, 1868, pl. Lxxxvill, fig. 471. Margaron (Unio) rowellii La, Syn., 1870, p. 35- Nephronaias rowellii Stupson, Syn., 1900, p. 594. Rather more inflated and pointed behind than N. macnielit, somewhat more inflated and darker colored than U. goascor- anensis, darker and less rayed than N. oregonensis. These four species are very difficult to separate and Dr. Lea had all four of them in his collection labeled Unio rowelli. NEPHRONAIAS HJALMARSONI (Dunker). Shell small, irregularly long elliptical, moderately com-' pressed, narrowed and rounded in front, rather wider and subtruncate above at the posterior end; posterior ridge strong, scarcely double, ending in a blunt point near the base line of the shell; beaks but little elevated, about one-third of the way back from the anterior end; base rounded; surface covered with strong, concentric, sometimes anastomosing’ plaits; epi- dermis dirty yellow; pseudocardinals somewhat thick, oblique, deeply furrowed but not crenulated ; nacre bluish-white. Length 36, height 18.5, diam. It mm. Rio Chamelicon, Honduras, near Guatemala. (Jnio hjalmarsoni DunxkErR, Mal. Blatt, V, 1858, p. 227.—VvoNn Martens, Biol. Cent. Am., Moll., 1900, p. 500, pl. XX XVII, figs, Ld: 264 NEPHRONAIAS Von Martens figures for the first time this hitherto almost unknown species. I scarcely know where to place it, as it does not have any very decided characters. It may be a male shell, not quite mature, of the genus Nephronaias, or it is possibly a Unio and related to U. aratus, though the form is quite dif- ferent. N&EPHRONAIAS GOASCORANENSIS (Lea). Shell elongated, scarcely inflated, subelliptical to subtrian- gular ; dorsal line curved gradually at the hinge and more sharp- ly behind ; base line nearly straight in the male, curved outward at the posterior base in the female shell; posterior ridge low, somewhat double; beaks full, moderately high, their sculpture consisting apparently of nearly concentric, fine ridges ; epider- mis smoky-olive in the younger shells, dirty brownish in old shells, slightly sulcate, rather smooth in young shells, scarcely rayed even when young; left valve with two small pseudocar- dinals, and two curved laterals; right valve with one pseudo- cardinal with a very small tooth above and one lateral; mus- cle scars well impressed, the anterior rough. Length 60, height 33, diam. 20 mm. Goascoran River, Honduras; Tehuantepec; Chiapas, Mexi- co; W. Guatemala; Estero Real, Nicaragua. Unio goascoranensis Lea, Pr. Ac. N. Sci., Phila., II, 1858, p. 118; Jl. Ac. N.Sei.. Phila.; TV, 1860, p: 256; pl. xi, ne: 146; Obs., VII, 1860, p. 76, pl. x11, fig. 139—von MAarTENs, Biol., Cent. Am., Moll., 1900, p. 501, pl. xxxvut, figs. 10, 10a. Margaron (Unio) goascoranensis Lua, Syn., 1870, p. 45. Nephronaias goascoranensis SIMPSON, Syn., 1900, p. 594- Unio guatemalanus von Martens, Biol. Cent. Am., Moll.,. 1900, p. 519, pl. xxxviil, figs. 7-8a. It is extremely difficult to state the differences between this form and some of the near related species. The young are more delicate and smoother than those of rowellii and at all stages it is less inflated and more blunt behind than that. species. NEPHRONAIAS 265, After carefully comparing von Martens’ description and fig- ures of his Unio guatemalanus with numerous specimens from various localities I am satisfied that it is this species. Lea’s shells (which he has labeled Unio rowelli) from Nicaragua, agree very well with von Martens’ description, and they cer- tainly are J,ea’s goascoranensis. NEPHRONAIAS DYSONII (Lea). Shell solid, élliptical, scarcely inflated, strongly and regular- ly sulcate, subbiangular behind, with one or two somewhat angular posterior ridges, the lower the stronger ; beaks slightly prominent ; ligament light brown; epidermis straw-colored or tawny with one or two darker rays on the posterior slope along as many slight, radial impressions; left valve with two sub- compressed, ragged pseudocardinals, with often a third smaller one between them, and two curved laterals, the upper the smaller; right valve with two pseudocardinals, the upper much compressed, and one lateral; muscle scars impressed; dorsal scars on the under side of the hinge plate and the posterior base of the hinder pseudocardinal; beak cavities not deep; nacre white, rather silvery. Male shell slightly and evenly curved on the base, the pos- terior end a little elevated. Female shell with a moderate post- basal inflation, the posterior end of the shell higher than in the male. Length 50, height 32, diam. 17 mm. Honduras; Costa Rica. Unio dysonii Lea, Pr. Ac. N. Sci. Phila., XI, 1859, p. 152; jl. Ac. N. Sci. Phila., IV, 1860, p. 252. pl. XxxIx, fig. 132; Obs., VII, 1860, p. 70, pl. xxx1Ix, big. 132. Margaron (Unio) dysonti Lea, Syn., 1870, p. 35. Nephronaias dysonii Stimpson, Syn., 1900, p. 594. The type is not in the Lea collection, but belonged to Cum- ing, and is apparently a young female shell. There are several shells in the National Museum collection from San Carlos, Costa Rica. which agree so closely with Lea’s description and 266 NEPHRONAIAS figures, that I can have but little doubt that they are his species. ‘Chey are a trifle narrower behind than the type and the epidermis is darker in the vicinity of the beaks. The shell is occasionally faintly raved. NEPHRONAIAS FLUCKI Bartsch. “Shell elliptical, moderately inflated, attenuated posterio- ventrally ; sloping gently and evenly dorsally from a line ex- tending from the umbones to the posterior ventral angle. Dorsal line evenly arcuate, curving a little more abruptly an- teriorly than at the posterior end; ventral margin almost straight or slightly concave. In some, presumably the females, the shell is somewhat drawn out ventrally at the posterior margin, and in such the ventral outline necessarily appears more concave. Surface marked by numerous very strong, concentric lines of growth and crinkly, radiating rays, which are more pronounced on the anterior end, gradually fade out from the middle of the shell posteriorly. Periostracum shin- ing, dark brown at the umbones, fading gradually to greenish- yellow at the edge. Umbonal cavity moderately deep. Pseu- docardinal of the right valve strong, triangular, deeply notch- ed, (almost bifid, by the deep, vertical /\-shaped notch in old specimens), with numerous, fine, secondary notchings. Pseu- docardinals of the right valve rather slender, finely notched, inclosing a /\-shaped cusp between them, which corre- sponds to the /\-shaped notch in the other valve. Laterals narrow, slightly arcuate and obliquely ridged. Dorsal mus- cle scars feeble. Nacre bluish-white at the margin, shading to livid-olive dorsally. Length 64, height 26.7, diam 17.6 mm.” (Bartsch). Type locality, Wounta River, northwest of Kukallaya, Nic- aragua. Nephronaias flucki Barrscu, Pr. U. S. Nat. Mus., 1906, XXX, p. 393, pl. xxvit, figs. 2, 3; XXVIII, figs. 2, 3; XXIX, figs. I, 3. NEPHRONAIAS 267 oe N. flucki can be readily separated from the other Nephro- naias of the region by its rugose sculpture, in which respect, it resembles N. dysoni Lea, from Costa Rica, and by its wavy, radiating lines and the dark nacre.”’ NEPHRONAIAS TEHUANTEPECENSIS (Crosse and Fischer). Shell inequilateral, elliptic rhomboid, moderately inflated, solid,, concentrically sulcate ; posterior ridge rather prominent and more or less double, ending behind in a slight biangula- tion; epidermis tawny to brownish-black, rayless; ligament brown; left valve with two solid, radial pseudocardinals and two delicate laterals; right valve with one strong pseudocar- dinal and an obsolete tooth above it with one strong lateral ; muscle scars well impressed; dorsal scars under the hinge plate ; nacre white, straw-colored or salmon. Male shell nearly or quite straight on the basal line; female shell with a slight marsupial swelling. Length 68, height 38, diam. 25 mm. Length 58, height 33, diam. 22 mm. San Efigenia, Oaxaca, Mexico; Capunta, Honduras, in the Patook River. Unio tehuantepecensis Crosse and Fiscuer, J. de Conch., XLI, 1893, p. 296.—FiscHER and Crosse, Miss Sci., lI, 1894, p. GIS, .plaLxV, ties. 3. 3q,4. Nephronaas tehuantepecensis SIMPSON, Syn., 1900, p. 504. An oblong, sometimes long ovate, shell, which is smoother, more inflated and less biangulate behind than its near ally, N. copanensis. NEPHRONAIAS COPANENSIS (von Martens). Shell subrhomboid, subinflated, very solid when old, inequi- lateral, covered with a tawny brown or blackish, rough epider- mis, which is generally sulcate; posterior ridge double, the two ridges widely separated, usually angular and distinct and ending behind in a decided biangulation ; beaks probably mod- erately full, but in all the specimens seen very badly eroded away; left valve with two strong, triangular, ragged pseudo- 268 NEPHRONATAS cardinals with a smaller one between them and two remote laterals, right valve with one strong, ragged pseudocardinal and sometimes a vestigial one above it, with one small lat- eral; beak cavities shallow with a large number of dorsal scars extending forward under the teeth; muscle scars well impressed; pallial line well marked, sometimes crossed by radiating furrows; nacre bluish-white, white or yellow to bright orange, in one or two shells purplish. Length 70, height 38, diam. 24 mm. Length 75, height 41, diam. 25 mm. Rio Copan, Guatemala (type) ; Honduras, various localities (I.ea collection). Unio tehuantepecensis var. copanensis VON Martens, Biol. Cent. Am., Moll., 1900, p. 502, pl. xxxv1, fig. 6, 6a. A considerable number of shells of this form, part of them from the type locality from von lhering are in the National Museum collection, others are in the Lea collection from Hon- duras labeled scamnatus. This is a stronger, more rude, more arcuate shell than U. tehwantepecensis and much more decid- edly biangulate behind and I have no hesitation in considering it worthy of specific rank. ‘The Museum shells all agree very well with von Martens’ figures and description, but show con- siderable of variation. All have the nacre thickened in front. I cannot refer any of the shells I have seen from Cuba to this species. One young specimen in the National Museum is slightly inflated in the post-basal region and may be a female Group of Nephronaias reticulata. Shell evenly elliptical, slightly biangulate behind, solid and inflated ; surface covered with fine, concentric ridges and hav- ing delicate radiating furrows, which cut the sulcations and form them into loops. NEPHRONAIAS RETICULATA Simpson. Shell evenly long elliptical, subinflated, rather solid, with a low, somewhat double posterior ridge, which ends in a scarcely perceptible biangulation behind; beaks but slightly elevated, NEPHRONAIAS 269 much eroded in the only specimens seen; ligament very pale brown or tawny; surface generally slightly sulcate ; epidermis tawny, rayless, with impressed or elevated radiating lines, between which it is looped and wrinkled like dried paint; left valve with two small, stumpy, radiating pseudocardinals and two curved laterals; right valve with one solid pseudocardinal, a small, compressed tooth above it and one lateral; muscle scars impressed, the anterior ones roughened; pallial line dis- tinct, marked with radiating sculpture; nacre soiled white, lurid in the cavity of the shell; dorsal scars numerous, placed under the hinge plate. Length 50, height 32, diam. 20 mm. Patook River, Honduras; Rio del Miro, Nicaragua. Nephronaias reticulatus Stmpson, Pr. Ac. Sci. Phila., 1goo, p. 779 Pla Wipes 3) SYM: TEOO,, Pr 595- The only specimens seen by the writer seem to differ from all related species in having an almost evenly elliptical form. The posterior end of the shell shows a narrow, scarcely per- ceptible biangulation and the anterior end is narrowed into a rounded point. It is also remarkable for the peculiar epider- mal sculpture, much like that of Plagiola encarpus. The only two shells I have seen are probably females. Group of Nephronaias aztecorum. Shell oblong, solid, incurved on the base, having the greatest diameter at or behind the middle; beaks full; pseudocardinals ‘small; epidermis brown, sometimes faintly rayed; female shell with a well-developed marsupial swelling. Animal unknown. NEPHRONAIAS AZTECORUM (Philippi). Shell oblong, inequilaterai, slightly inflated, the greatest diameter being at or behind the center, varying from subsolid to solid, rounded in front, arcuate at the base; beaks rather high but generally subcompressed; epidermis brown, some- times feebly rayed; pseudocardinals small; laterals curved; nacre white or purple. 270 NEPHRONAIAS Male shell either rounded or broadly subbiangulate behind, often obliquely subtruncate above, arcuate below. Female shell with a well-developed marsupial swelling, the posterior point much more elevated than it is in the male. Length 60, height 32, diam. 18 mm. Length 112, height 56, diam. 42.5 mm. Mexico. Unto ‘astecorum Puixipri, Zeits. fur Mal., IV, 1847, p. 95; Abbild., I1I, 1849, p. to9, pl. v1, fig. 2.--Kustrer, Conch. Cab. Unio, 1862, pp. 2, 84, pl. xcv, fig. 6—von MArTENS, 3i01. Cent. Am., Moll., 1900, p. 502, pls. xxxvi, figs. 2-4, XXXVII, figs. 3, 3a, 3b. Margaron (Unio) aztecorum Lata, Syn., 1870, p. 44. Lampsilis astecorum SiMPSON, Syn., 1900, p. 572.—PILsprRy, Pr. Ac. N: ‘Sei. Philay 1006; 9:52: I am a good deal in doubt as to this species, which I placed in Lampsilis in the Synopsis. Philippi’s figure is poor and it probably represents a female. Von Martens figures a number of specimens, some of which agree fairly well with Philippi’s figure and others differ widely from it. If von Martens is correct the species should go in Nefphronaias, as the males are arcuate below and sometimes biangulate behind, characters which do not belong to Lampsilis. He is mistaken, I believe, in referring the Unio strebelii I,ca to this species as a variety. I am sure that it is a synonym of N. medellina. Unio emargin- atus lea, which he seems to think may be aztecorum, is, I am almost sure, a palearctic species. The larger dimensions given are for one of von Martens’ shells. Var. chapalanus von Martens. “Somewhat higher comparatively, especially in its hinder part; brownish-yellow, with some green rays; ventral margin scarcely concave; cardinal teeth more feeble; inside white. Length, 60, alt. vert. 31.5, ala 32, diam. 20 mm. Vertices in % long.” (von Martens. ) Type locality, Laguna de Chapala, Central Mexico. NEPHRONAIAS 271 Unio astecorum var. chapalanus voN Martens, Biol. Cent. Amer., Moll., 1900, p. 504, pl. xxxvi, figs. 5-5a. “From U. poeyanus, which belongs also to the Pacific slope of Mexico, this form is distinct by the comparatively higher shell, the height being in chapalanus a little more than one- half, in poevanus a little less than two-fifths the length.” NEPHRONAIAS SOLEDADENSIS (Crosse and Fischer). “Shell inequilateral, elliptic-oblong, elongate, subcompressed, narrowed in front, somewhat expanded posteriorly, rather thick, epidermis olive-brown, concentrically striate; anterior and posterior margins rounded; basal margin nearly straight; dorsal margin slightly curved: Nacre a beautiful purplish- violet. Right valve with two unequal pseudocardinals (the upper obsolete, the lower short, thick, grooved), and a lamell- iform lateral. Left valve with two pseudocardinals, the an- terior small, short, the posterior larger, grooved and two lamelliform laterals. Cicatrices of the anterior adductor mus- cles deep, suboval: those of the posterior adductors larger, superficial, suboval. Ligament brownish, not prominent. Length 67, height 33, diam. 20 mm.” (C. & F.) Type locality, La Soledad, State of Vera Cruz, Mexico. Unio soledadensis Crosské and Fiscuer, Jl. de Con., 1893, XLI, p. 111.—FiscHer and Crosse, Miss. Scient. Mex., Moll., 1894, II, p. 608, pl. LxIx, figs. 3, 3a-b. Unio aztecorum var. soledadensis VON Martens, Biol. Cent. Amer., Moll., 1900, p. 503. “This species appears to belong to the group of U. aztec- orum Phil., from which it differs by its larger size, more cyl- indrical and less inequilateral form, its longer and more atten- uated anterior extremity and more dilated posterior extremity. It can be distinguished from U. popei Lea by its more rounded, non-truncate and less elevated posterior end. Finally, it dif- fers from U. poeyanus Lea in its less inequilateral form, the non-concave ventral margin and the posterior extremity being more elevated than the anterior.” 272 NEPHRONAIAS Group of Nephronaias scamnata. Shell elliptical to elongate, compressed, strongly sulcate, rather solid, subbiangular behind; that of the female inflated at post-base ; epidermis olive to brown, sometimes feebly rayed ; beak sculpture delicate and but slightly marked, consisting of faint parallel ridges, which show a tendency to fall into two rounded loops; hinge rather solid; pseudocardinals stumpy, ragged, laterals straight; front part of the shell solid and suddenly becoming thinner behind; nacre bluish-white, salmon, or purple. Animal unknown. NEPHRONAIAS SCAMNATA (Morelet). Shell elongate rhomboid or long elliptical, compressed, ine- quilateral, subsolid, with a low, generally double posterior ridge ending in a feeble biangulation ; beaks not high but sharp, their sculpture consisting of fine, scarcely doubly-looped ridges, which differ little from the close, concentric sculpture that covers the entire shell; ligament long, narrow; epidermis blackish, brownish or olive, sometimes with a few faint, wide rays and occasionally having concentric tawny or light brown bands; left valve with two subtriangular, ragged pseudocar- dinals and two slender, nearly straight laterals; right valve with one strong pseudocardinal, a vestige of a second above it and one lateral; muscle scars superficial ; dorsal scars numer- ous under the posterior part of the pseudocardinals; nacre reddish or purplish, sometimes nearly white, slightly thicker in front. Male shell straight on the base or a little arcuate; that of the female somewhat produced at the posterior base, the two shells scarcely differing behind. Length 55, height 30, diam. 15 mm. Cuba; Honduras? Unio scamnatus Moretet, Test. Nov., No. 1, 1849, p. 30. Margaron (Unio) scamnatus Lea, Syn., 1852, p. 40; 1870, Dp. 35: Nephronaias scamnatus SIMPSON, Syn., 1900, p. 595: NEPHRONAIAS ag fe Umo proclinatus von Marrens, Biol. Cent. Am., Moll., 1goo, p. 508. Unio gundlacht Sowervy, Conch. Icon., XVI, 1866, pl. xiv, fig. 248. I am satisfied that there are at least two species of Naiades in Cuba, but it is very difficult without access to the types to say what names should be applied to them. The descriptions of Unio scamnatus by Morelet and U. gundlachi by Dunker are in Latin and inadequate to satisfactorily characterize these difficult and probably closely related forms. Von Martens, be- lieving that the names of Morelet and Dunker both apply to one species and that there are two diagnosible forms in the island, has applied a new name, Unio proclinatus, to the form I have described as NV. scamnata. Morelet states that the car- dinals of his shell are subtriaugular, that the epidermis is ful- vous-chestnut, and these are two characters, which apply to the species I have described and not to what I incline to believe is Dunker’s species, which has a brownish-green epi- dermis and compressed pseudocardinals. J have examined a large amount of material from Cuba and generally do not have the least trouble in separating the Uniones of that island into the two forms. Usually the species I have described is consid- erably more elongated than the other, though certain male shells approach closely in form; it is a little less inflated, the outline from a dorsal view showing an even curve from end to end, while that of what I believe to be gundlachi is most decidedly swollen at or behind the middle of the skull. U. scamnata is more strongly and evenly sulcate, the sculpture covering the entire shell, while in gundlachi it is often faint or wanting, especially just in front of the posterior ridge. N. scamnata is rayless or has broad, feeble rays; gundlachi is almost always rayed. And finally the female shell of scamnata appears to be but slightly fuller in the post-basal region than that of the male, while that of gundlachi is always well pro- duced, often as decidedly and extensivély so as that of Lamp- silis subrostrata. 274 NEPHRONAIAS I am very doubtful whether this species occurs on the main- land. Lea’s specimens from Honduras, which bear that name, are, | think, other species. I have seen specimens credited to Cuba, which approach very closely to Nephronatas tabascoen- sis, but I am not certain that the locality is accurate. I append the original description of Unio scammnatus. “Testa ovata convexo depressa, longitudinaliter tenuissime plicatula, castaneo-fulva, intus caerulescens ; umbones depressi, striatim de corticali; dens cardinals in valva dextra simplex, triangularis, in utraque compressus. Alt. 30, Lat. 55. Diam. 17. Cacajajicara, in insula Cuba.” NEPHRONAIS GUNDLACHI (Dunker). Shell elliptical or elliptic rhomboid, subsolid, subcompressed, somewhat inequilateral; most conspicuously inflated at or just behind the middle, in front of this the outline is wedge-shaped to near the front and where it rather suddenly narrows to the anterior point; posterior ridge scarcely developed, sometimes feebly biangulate, and ending in a faint posterior biangulation ; beaks low but sharp, their sculpture fine corrugated ridges, which are doubly looped; surface more or less sculptured with concentric ridges, which are generally less developed in front of the posterior ridge; epidermis smoky-olive to green- ish-vyellow, generally with more or less distinctly developed green rays; left valve with two subcompressed pseudocardinals and two delicate, nearly or quite straight, laterals; right valve with one subcompressed pseudocardinal, a vestigial one above, and one lateral; muscle scars rather shallow; dorsal scars. under the hinge plate and pseudocardinals. Nacre whitish, distinctly and often strongly tinted with blue, slightly iride- scent behind. The male shells are often nearly evenly elliptical, and some- times the length is only about one and a half times the width. They are nearly straight, rarely somewhat curved below. The female shell is wider ‘behind than in front and has a wide, rounded, often greatly developed marsupial swelling. Its pos- NEPHRONAIAS 275 terior point is high up on the shell ; it is sharper than that of the male and occurs at the end of a dark ray. Length (very large male) 92, height 50, diam. 30 mm. Length (male) 62, height 35, diam. 18 mm. Length (female) 65, height 40, diam. 23 mm. Cuba. Unio gundlachi DunKeEr, Mal. Blatt., V, 1858, p. 228. Nephronaias gundlacht Simpson, Syn., 1900, p. 595. Unio scamnatus VoN Martens, Biol. Cent. Am., Moll., 1900, pe 507: The original description is as follows: “U. testa ovata, paullo compressa, sulcis striisque subtilibus concentricis in- structa, epidermide tenui fusca, in speciminibus junioribus olivacea, vestita; umbonibus parum prominentibus decorticalis quartam paene testa partem occupantibus; margine dorsali leviter curvato, basali plus minusve ventroso; extremitate an- tica attenuata et rotundata, postica dilatata; dentibus cardinal- ibus crassiusculis, lateralibus augustis; margarita flavescente vel ccerulescente, posticum versus marginem flavescente. Flumine Taco Taco, Cuba.” The statements that this species is only slightly compressed, the dorsal margin is lightly curved, the basal inflated, the an- terior end narrowed and rounded, the posterior dilated, all apply to the shorter, less compressed, paler colored, smoother species, in which the female shell has a most decided marsupial swelling, and they do not apply to what I believe is the Unio scamnatus of Morelet. I have before me a female specimen of what I believe is gundlachi, which. is as decidedly swollen at the post-basal region as is any member of the genus Lampsilis. NEPIIRONAIAS ARUGINOSA (Morelet). Shell inequilateral, subrhomboid, moderately convex, solid. covered with a yellowish-chestnut epidermis, and having slight concentric sculpture; posterior ridge low, somewhat double, and ending behind in a wide, faint biangulation; beaks mod- erately elevated, smooth, according to the author of the spe- cies; left valve with one solid, somewhat ragged pseudocar- 276 NEPHRON AIAS dinal and two laterals; right valve with two pseudocardinals, the upper the smaller, and one lateral; anterior muscle scars oval, deep; posterior scars large, shallow; nacre bluish-white. Length 52, height 32, diam. 18 mm. River Michol, at Palenque, State of Chiapas, Mexico. Unio eruginosus Moreier, Test. Noviss., I, 1849, p. 29.— FiscHeR and Crosse, Miss. Sci., II, 1894, p. 596, pl. LX, figs. 2, 2a, 2b. Nephronaias eruginosus SIMPSON, Syn., 1900, p. 595: The shell figured by Fischer and Crosse is probably a young female. In the Lea collection there are three young shells from Comayaguan, Honduras, labeled Unio scamnatus that may belong to this species. They are quite pale colored and though worn, show faint rays. NEPHRONAIAS YZABALENSIS (Crosse and Fischer). Shell inequilateral, rhomboid elliptical, somewhat compress- ed, solid, with a low, double posterior ridge, which ends in a distinct biangulation behind; surface covered with concentric strie, slightly lamellated ; epidermis brown-olive with straight, green rays on the posterior slope; beaks small, not very prom- inent, their sculpture consisting of concentric ridges; left valve with one large, ragged pseudocardinal and a triangular pseudocardinal, with two laterals; right valve with two com- pressed pseudocardinals, the upper the smaller, and one lateral ; anterior muscle scars deep; posterior scars shallow; nacre bluish-white. The shell figured is no doubt a female, the basal line being decidedly rounded and full in the marsupial region ; the hinder biangulation is considerably elevated above the base line. Length 45, height 28, diam. 15.5 mm. Lake Yzabal, Guatemala. Unio yzabalensis CROossk and Fiscurr, J. de Conch., XL, 1892, p. 294.—Fiscner and Crosse, Miss. Sci., II, 1804, p. 597, pl. yxiv, figs. 4, 4a, 4b—von MARTENS, Biol. Cent. Am., Moll., 1900, p. 507, pl. xxx1x, figs. 9-TT. Nephronaias yzabalensis Simpson, Syn., 1900, p. 596. I have never seen this species, which seems to be distin- guished from other members of its group by being higher in proportion to its length. Von Martens’ figures, to and 11, represent male specimens. His fig. 9 is probably taken from a young shell. N&EPHRONAIAS RUGULOSA (Charpentier in Kuster). Shell oblong, rhomboid, compressed or subcompressed, solid, quite inequilateral, covered with close, distinct, concentric fur- rows; beaks rather high, their sculpture not observed ; epider- mis olivaceous or greenish-brown, often with hairlike, green- ish rays over the disk and one or more broader, distinct green and yellow rays on the posterior slope; pseudocardinals large, solid and ragged; laterals straight; muscle scars well im- pressed ; dorsal scars deep and numerous, extending from the center of the cavity along the base of the pseudocardinals ; cavity of the shell shallow; nacre rich purple. The figures of the two shells, which I refer to this species, are evidently taken from male shells and are nearly straight on the base. The lower end of the biangulation behind reaches nearly to the base of the shell. Length 52, height 28, diam. 14 mm. Mexico or Central America probably. Unio rugulosus CHARPENTIER in Kuster, Conch. Cab. Unio, 1856, p. 154, pl. xLiv, fig. 5. Nephronaias rugulosus SIMPSON, Syn., 1900, p. 590. The locality, “New Holland,” given in Kuster for this spe- cies is undoubtedly erroneous. It is evidently Mexican or Central American, and is, no doubt, a male shell of a species of Nephronaias. I have not seen authentic specimens of either this or Unio persulcatus Lea, but the two are certainly very close to each other. NEPHRONAIAS PERSULCATA (Lea). Shell long rhomboid, rather compressed, subsolid with a low, rounded posterior ridge, which ends in a scarcely percep- table biangulation behind, covered throughout with close, fine, 278 NEPHRONATAS concentric sulcations ; beaks near the anterior end, rather full, their sculpture not observed; anterior and posterior ends rounded below, subtruncate above; base line very slightly rounded; epidermis greenish-brown, with numerous hair-like rays; pseudocardinals large, double in the left valve, consid- erably split up; laterals long and straight; muscle scars im- pressed; dorsal scars numerous, deep, extending from the center of the cavity along the base of the pseudocardinals ; cavity of the shell very shallow ; cavity of the beaks shallow ; nacre dark purple, 1ridescent. Length 52, height 28, diam. 14 mm. Mexico. Unio persulcatus Lea, Pr. Ac. N. Sci. Phila., XI, 1859, p. 153; Jl. Ac. N. Sci. Phila.., IV, 1860, p. 255, pl. xu, fig. 135; Obs., VII, 1860, p. 73, pl. xu, fig. 135 —Muscrave, Phot. Conch., i563, pili, fie. 3. Margaron (Unio) persulcatus Lea, Syn., 1870, p. 36. Nephronaias persulcatus SIMPSON, Syn., 1900, p. 596. Unio cuprinus persulcatus von Martens, Biol. Cent. Am., Moll., 1900, p. 505. Dr. Lea states that this species has a sharp, compressed keel on the posterior slope, and that there is a single broad yellow ray in this region, extending from the beak to the mar- gin. The outline of the shell is almost exactly like that of Char- pentier’s Unio rugulosus, the only difference being that in Lea's shell the heaks are placed a little farther forward. Charpen- tier’s species has four broad, yellowish bands on the posterior slope, alternating with an equal number of green ones, and has heavy pseudocardinals and shining purple nacre. While I do not feel justified in uniting the two I strongly suspect that they are mere forms of one and the same thing. NEPHRONATAS MICRODON (von Martens). Shell long rhomboid, subsolid, scarcely inflated, with feeble, concentric sculpture; beaks moderately full, their sculpture not observed; epidermis dirty olive to brownish, with feeble rays on some young shells; pseudocardinals small, two in the NEPHRONAIAS 279 left valve and two in the right; two laterals in the left valve and one in the right; pseudocardinals showing a disposition to blend together and become tuberculous in the old shells; anterior scars impressed’; posterior scars round, superficial ; nacre bluish-white or white. In the type, an old male shell, the base is almost straight. In three younger shells in the National Museum collection the post-basal region is slightly produced. Iength 107, height 57, diam. 34 mm. Length 93, height 50, diam. 29 mm. Guatemala, Rio de las Salinas (Stoll), and Systeme de Po- lochic (von Thering). Unio microdon von Marrens, Biol. Cent. Am., Moll., 1goo, Dr 504, DE ER, fies. 1 a-C, I am not positive as to the systematic position of this species as I am not certain that the young, somewhat broken and erod- ed shells in the National Museum collection are the same as von Martens’ species. One of these is as large as N. calami- tarum and resembles it somewhat, but is much thinner and is evidently a young shell. It appears to show something of the blending together of the pseudocardinals, which is so marked a character in von Martens’ shell. A younger fresh valve shows faint rays and a bluish-white nacre. NEPHRONAIAS CALAMITARUM (Morelet). Shell very inequilateral, subcompressed, rather solid, some- what elongated and subrhomboid, with a low, rounded or feebly biangulate posterior ridge; beaks scarcely elevated, compressed but sharp, their sculpture consisting of fine, con- centric ridges, which are sometimes feebly corrugated and doubly looped, this sculpture gradually passing into the fine, concentric ridges that cover the surface of the shell; there is often a radiating groove on the posterior slope and this 1s sometimes replaced by a feeble, dark ray; there are occasion- ally a few faint rays behind on the younger shells, otherwise the surface is yellowish-green in the young and darker in the old specimens; left valve with two triangular, radial, some- 280 NEPHRONAIAS what split or roughened pseudocardinals and two straight or slightly curved laterals; right valve with one pseudocardinal and sometimes a vestigial one above it with one lateral; there are often indications of a low tooth between the two sets; beak cavities compressed, with several dorsal scars; muscle scars well impressed, the anterior ones rough; nacre whit- ish, rose or faint purple, scarcely thickened in front and show- ing a feeble, radiating groove below the laterals. Male shell with a straight or arcuate base line; that of the female a little produced at the posterior base. Length 50, height 26, diam. 14 mm. Mexico, Palenque, in the State of Chiapas. Unio calamitarum More.er, Test. Noviss., I, 1849, p. 30.— Fiscuer and.Crossr, Miss. Sci., IT, 1894, p. 612, pl. LxmI, figs. 5, 5a. Margaron (Unio) calimatorum L&A, Syn., 1870, p. 63. Nephronaias calimatarum Simpson, Syn., 1900, p. 596. Unio cuprinus voN Martens, Biol. Cent. Amer., Moll., 1900, p. 505. According to Fischer and Crosse in the Mission Scientifique the figure given by Sowerby is not typical, but a variety which they call nephritica. Certainly this figure does not closely agree with either their description or figures, and it looks to me like that of a different species. Specimens in the National Mu- seum from Palenque in Chiapas, Mexico, Morelet’s locality for this species, agree with the description of Fischer and Crosse and their figure of what they call var. prolongata. By an oversight the name was misspelled in the Synopsis. Var. arcuans (Fischer and Crosse). Shell relatively short, oval, subtriangular; posterior end at- tenuated ; dorsal border arcuated. Length 47, height 27.5, diam. 17 mm. Unio calamitarum var. arcuans Fischer and Crosse, Miss. Sci., II, 1894, p. 613, pl. ux1v, figs. 5,. 5a. Unio cuprinus var. arcuans voN Martens, Biol. Cent. Amer., Moll., 1900, p. 506. NEPHRONAIAS 281 I have never seen this variety, which seems to be shorter than the type, and according to the figures, more distinctly. ~biangulate behind. Var. nephritica (Fischer and Crosse). Shell subrhomboid, somewhat arcuate, the base line being incurved, scarcely biangulate behind, the almost rounded, low, posterior ridge ending at the level of the base. ? Unio calamitarum Sowerry, Conch. Icon., XVI, 1868, pl. LXXIV, fig. 385. Unio calamitarum var. nephritica FiscHE~rR and Crossr, Miss- Sci., II, 1894, p. 613. Unio cuprinus var. nephriticus voN Marrens, Biol. Cent. Amer., Moll., 1900, p. 505. It is quite probable that this is the male shell and that var. arcuans is the female of one and the same thing, though this form is much less biangulate behind. If this should be the case the name arcuans would take precedence. Var. subventralis (von Martens). “Ventral margin distinctly convex. one V5, aliavvert. 20, aie 20; diam. 18mm. Vertices in 3/10 long.’ (von Martens. ) Type locality, Mexico. Unio cuprinus var. subventralis voN Martens, Biol. Cent- Amer., Moll., 1900, p. 506, pl. Xxxv1, figs. 1, Ia, b. NEPHRONAIAS TABASCOENSIS (Charpentier in Kuster). Shell somewhat elongated, subrhomboid, scarcely inflated, solid, with a low, slightly double posterior ridge, which ends in a feeble biangulation behind; beaks low, placed well forward, their sculpture not observed; surface sculptured with fine concentric sulcations; epidermis dark, rayless; left valve with two strong, radiating, somewhat split-up, pseudocardinals, a rather wide, flat hinge plate, and two laterals, the lower the heavier; right valve with one strong pseudocardinal and one heavy lateral ; there are sometimes faint, oblique teeth between them; beak cavities compressed, rather deep, with numerous 282 NEPHRONAIAS dorsal scars; muscle scars well impressed, the anterior ones rough; nacre rich coppery-purple, slightly iridescent behind ; pallial line crossed by faint, radiating ridges. Male shell decidedly long rhomboid, with a straight base line, the lower posterior ridge ending at this line. Female shell slightly obovate, subrhomboid ; the base line rounded and somewhat produced behind the middle; lower posterior ridge ending above the base. Length (male) 58, height 35, diam. 19 mm. Tabasco, Mexico; small stream near Punta Gorda, Belize, Honduras. Unio tabascoensis CHARPENTIER in Kuster, Conch. Cab. Unio, TSS, p/053, ply SLIV, Mees. Margaron (Unio) tabascoensis Lwa, Syn., 1870, p. OF. Nephronaias tabascoensis SIMPSON, Syn., 1900, p. 596. Unio cuprinus tabascoensis von Martens, Biol. Cent. Am., Moll., 1900, p. 505. The shell figured in Kuster is a male and is straight on the base line and has a considerably developed posterior point. Its outline is almost exactly that of the Unio persulcatus Lea, and it differs from that species only in having a silvery instead of a purple nacre and in being uniform colored, while persulcata has a yellow band reaching from the beaks to the posterior region. NEPHRONAIAS PLICATULA (Charpentier in Kuster). Shell elongately obovate, inequilateral, somewhat convex, densely concentrically ridged; beaks longitudinally undulately plicate, rather prominent ; epidermis fuscous-olive ; pseudocar- dinals bipartite, solid; laterals rather remote, moderate ; nacre beautiful violet, shining. Mexico, Punta Gorda, Belize; Honduras. Unio plicatulus CHARPENTIER in Kuster, Conch, Cab. Unio, 1856, p. 154, pl. xiv, fig. 4. Nephronaiias plicatulus Simpson, Syn., 1900, p. 597- The figure in Kuster no doubt represents a female shell, as the base line is rather strongly curved, especially in the region NEPHRONAIAS 252 of the marsupium. There is a shell in the National Museum collection from Belize, which is probably a male of this species, which is a little shorter than Kuster’s figure, is more distinctly biangulate behind, and has a nearly straight base line. An- other shell in the Lea collection from Honduras I would refer to this. It is a male and has salmon and purple-tinted nacre and seems to stand between plicatula and tabascoensis. In- deed I think it quite probable that the two species mentioned, Lea’s Unio persulcatus and Charpentier’s rwgulosus are all forms of one species varying a little in form, color of nacre and epidermis, and in the position of the beaks. NEPHRONAIAS RAVISTELLA ( Morelet). Shell small, inequilateral, subrhomboid, rather compressed, strongly concentrically striated; beaks apparently low, their sculpture not seen; epidermis brown; left valve with two solid pseudocardinals and two laterals ; right valve with two pseu- docardinals and a single lateral; anterior muscle scars deep, semicircular; posterior scars suboval, well marked; nacre whitish, tinted lead-color or yellowish-brown. Fischer and Crosse figure two shells, both badly eroded but apparently having a double posterior ridge, which ends in a distinct, wide biangulation behind. One of these shells is a male and is decidedly arcuate on the base line, the lower part of the biangulation being on the line of the base; the other is probably a female and has the base line curved and full be- hind the middle, the base of the hinder biangulation being slightly raised. Length 30, height 21, diam. 13.5 mm. Guatemala: Tabasco, Mexico. Unio ravistellus Moreiet, Test. Noviss., No. 1, 1849, p. 29.— Kuster, Conch. Cab. Unio, 1856, pl. xin, fig. 6.—SoOwWERBY, Conch. Icon., XVI, 1868, pl. Lxxtt, fig. 366 ?>__ FyiscHER and Crossr, Miss. Sci., II, 1894, p. 609, pl. Lx1, figs. 4, 5, and sa.—von Marrens, Biol. Cent. Am., Moll., 1901, p. 516, pl. XXXVILI, figs. 2-6a. Margaron (Unio) ravistellus Lua, Syn., 1870, p. 40. Nephronaias ravistellus Stupson, Syn., 1900, p. 597. 284 NEPILRONATAS I have never seen the type of this species nor anything more than a single valve of what is probably an authentic specimen, but if Fischer and Crosse’s figures are correct I am a little doubtful whether it can equal Sowerby’s Unio vellicatus, as von Martens believes. The National Museum. possesses spec- imens, which agree almost absolutely with the original figure and description of vellicatus and it 1s a peculiar species. More- let's species seems to be solider and more decidedly biangulate behind, yet the two forms may run together. Von Martens figures a young female shell with rays. Von Martens makes the Unio vwere-pacis of Tristram a variety of the above, and fig- ures it. Hus figure certainly is the same as that of the Unio vellicatus Reeve in the Conchologia. ‘Tristram’s description does not seem to me to agree with this, as he says his shell has a shining purple nacre, while that of vellicata is dull lurid and ashy-brown. Var. majuscula (von Martens). “Of larger size; the summits somewhat more advanced. Long. 59, alt. vert. 27, ale 28, diam. 17.5 mm. Long. 58, alt. vert. 26, ale 27, diam. 17.5 mm. Long. 55, alt. vert. 26, ale 27, diam. 20 mm. Vertices in 2/7 long.” (von Martens. ) Type locality, Lake of Yzabal, E. Guatemala. Unio ravistellus var. majusculus VoN Martens, Biol. Cent. Amer., Moll., 1900, p. 516. “The dimensions given above show that this form varies considerably in the general outlines.” NEPHRONAIAS VELLICATA (Reeve). Shell rather small, long elliptical or long rhomboid, sub- solid, somewhat convex, inequilateral, with a well-developed, generally double, posterior ridge; beaks moderately full, their sculpture not seen; surface delicately concentrically ridged; epidermis smoky-brown, rayless in adult specimens; left valve with two subcompressed pseudocardinals and two curved lat- erals ; right valve with one pseudocardinal, often with a second NEPHRONAITAS 285 small one above it, and one lateral; beak cavities shallow: muscle scars not deep, the anterior ones single; nacre whitish or grayish. Male shell long rhomboid, the base line slightly curved or straight, in old specimens a little incurved: lower posterior . ridge ending at the base lines. Female shell decidedly pro- duced in the region of the marsupium, the posterior biangula- tion elevated above the base line. Length (male) 43, height 24, diam. 15 mm. Length (female) 45, height 26.5, diam. 15 mm. Yzabel, Guatemala. Unio vellicatus Reeve, Conch. Icon., 1865, pl. xxtr, fig. 103.— FiscHER and Crossr, Miss. Sci., I, 1894, p. OIo. Nephronaias vellicatus Simpson, Syn., 1900, p. 597. Umo ravistellus von Marrens, Biol. Cent. Am., Moll., 1goo, peso; pl XXXVI, fir. F. Reeve’s figure represents a female shell, which differs a good deal in form from that of the male. Von Martens believes that this equals Morelet’s Unio ravistellus, but Fischer and Crosse claim that it does not. There are shells in the National Museum, which came from Yzabel, Guatemala, that agree per- fectly well with Reeve’s figure and description, but are not nearly as heavy nor so widely and distinctly biangulate behind as are the figures given by von Martens. Sowerby’s figure of ravistellus in the Conchologia may be a young shell of that, but I suspect that it is vellicata. NEPHRONAIAS MELLEA (Lea). Shell regularly elliptical, scarcely inflated, inequilateral, rather solid, thicker in front, beaks prominent and minutely undulated; surface sulcated throughout ; epidermis honey-yel- low, bright, obsoletely rayed; posterior ridge rather full and rounded, scarcely double in the specimen figured; pseudocar- dinals rather large, erect, crenulate, two in each valve, laterals nearly straight, elongated, double in each valve: anterior cica- trices impressed, posterior cicatrices confluent; dorsal cica- trices placed under the hinge plate behind the pseudocardinals - 286 GLEBULA cavity of beaks deep and angular; nacre salmon-colored, iridescent. Length 52, height 28, diam. 16 mm. Mexico or Central America, no doubt. Unio melleus Lea, Pr. Ac. N. Sci. Phila., XI, 1859, p. 152; Jl. Ac, N.. Set. Phila., TV, 1860; p. 250, pl. xxxvalr, fe. 120; Obs., VII, 1860 p. 68, pl. xxxviu, fig. 129.— ReEve, Conch. Icon., XVI, 1865, pl. xx1, fig. 92. Margaron (Unio) melleus Lea, Syn., 1870, p. 35. Nephronaias melleus SIMPSON, Syn., 1900, p. 597. Dr. Lee states that the type of this species is in the Cun- ningian cabinet, and there are no specimens in his collection. Judging from the figures and his description I believe it to be a female shell of some species of Nephronaias of the scam- nata group. Lea remarks that it is nearest to his Unio aratus. Though the typical Unio dysonii is shorter and considerably wider behind than the figure Lea gives of this species, I think it quite likely that the two may run together, as there are shells in the National Museum collection, which are somewhat inter- inediate. Genus GLEBULA Conrad, 1853. Glebula Conrap, Pr. Ac. N. Sci. Phila., 1853, p. 268. Shell solid, much inflated, short elliptical, bluntly pointed and slightly biangulate behind, with a low, posterior ridge; female shell swollen at post-base; beaks compressed, destitute of sculpture; epidermis brownish, cloth-like; pseudocardinals divided into irregularly radiating, granular laminz, sometimes to the number of a dozen or more in each valve; hinge plate reduced to a mere rounded line behind the pseudocardinals ; laterals short, remote; anterior adductor scars deep, smooth; there is in each valve only a single. large, semicircular pos- terior scar with a straight edge in front ; dorsal scars numerous, distinct, placed hack of the pseudocardinals ; cavity of the beaks not deep or compressed ; nacre dull lurid to purplish-brown. Animal with gills nearly equal in size, inner slightly the larger in front, united the whole length to the abdominal sac ; marsupium occupying the hinder half of the outer gills; ovi- GLEBUL«A 287 sacs separated from each other by a sulcus as in Lampsilis; palpi very large, wide, wrinkled ; mantle having a wide, slightly thickened border, double edged, the inner being beautifully toothed; branchial opening papillose; anal crenulate; foot small. Type, Unio rotundata Lamarck. At the time of writing the Synopsis I felt a little doubtful as to the systematic position of this peculiar and isolated form. Recently Mr. Lorraine S. Frierson, who has been making a careful study of the anatomy and shell characters of the Unio- nid of Louisiana has discovered that the beaks of perfect specimens show no sculpture whatever. He has examined gravid specimens and finds that the marsupium occupies the hinder part of the outer gills, much as in Lampsilis. On pres- sure the ovisacs were extruded from the gills, they were flat- tened in cross section and were about one-half of an inch in length. The shell of this form is quite different from that of any other I know, seeming to combine some of the characters of Lampsilis and some of those of Quadrula. It is short, rather inflated, often solid, subtriangular or short elliptical and is often more or less biangulated behind, the latter character rarely being seen in the slightest degree in Lampsilis. ‘The pseudocardinals are curiously radically split. These radial lamella are often sharply serrate and they re- call the teeth of some of the South American species of Diplo- don. It is probable that the apparent radial sculpture shown in eroded specimens in due to a real radiating structure of the shell. This character exists in many Naiades as well as in some of the heavy species of Venus, but does not appear unless the shell has begun to disintegrate. GILEBULA ROTUNDATA (Lamarck). Shell somewhat elliptical, inflated, rather solid; beaks gen- erally flattened or compressed, though often full in old speci- mens, without sculpture ; posterior ridge moderate, angular and sometimes slightly double: epidermis brownish, cloth-like in 288 GILEBULA unworn shells, not rayed; left valve with two pseudocardinals, which are often split up into numerous radiating, nodulous lamellz, with two remote laterals, the lower the larger; right valve with two pseudocardinals, the upper small and com- pressed, the lower much split up, and one lateral, which is sometimes slightly double; hinge plate narrowed and rounded in front of the laterals; beak cavities moderate, not com- pressed, showing numerous dorsal scars under the hinge plate; muscle scars large, impressed, smooth, the posterior one semi- circular; nacre dull purplish. Female shell slightly inflated at posterior base, sometimes having a slight sinuosity behind the swelling. Length 95, height 72, diam. 53 mm. Length 73, height 57, diam. 43 mm. Length 80, height 54, diam. 32 mm. Louisiana; eastern Texas; Rio Grande River; Escambia County, Florida. Type locality, not given. Unio rotundata LAMARCK, An. sans Vert., VI, 1810, p. 75. Glebula rotundata Conran, Pr. Ac. N. Sci. Phila., 1853, p. 268. SIMPSON, Syn., 1900, p. 598. Unio rotundatus HANEY, Biv. Shells, 1843, p. 201, pl. xx111, fig. 30.—KusteEr, Conch. Cab. Unio, 1861, p. 256, pl. LXxxv1, fig. 4.—Reeve, Conch. Icon., XVI, 1865, pl. xxu1, fig. 106.— Cary, Tr. Ac. Sei. St. Louis, Vill. 1805op. 47, pla, Margarita (Unio) rotundatus Lea, Syn., 1836, p. 33; 1838, p- 23. Margaron (Unio) rotundatus Lea, Syn., 1852, p. 34; 1870, Pp. 5. Unio suborbiculata LAMARCK, An, sans Vert., VI, 1810, p. 81. Unio suborbiculatus Frrussac, Guer. Mag., 1835, p. 26. Unio glebulus Say, Trans. Jl., IV, 1831, p. 526; Am. Conch., 1832, pl. xxx1v.—CHENU, Bib. Conch., 1st ser., III, 1845, p. 46, pl. x1, fig. 10-12.—Sowerrpgy, Conch. Icon., XVI, 1868, pl. LxxIv, fig. 384. Unio subglobosus Lea, Tr. Am. Phil. Soc., V, 1834, p. 30, pl. tt, fig. 3; Obs., I, 1834, p. 142, pl. 1, fig. 3 —Sowerny, Conch. Icon., XVI, 1868, pl. Lxrv, fig. 32T. qn OBOVARTA 289 Unio granadensis Conrap, Pr. Ac. N. Sci. Phila., VII, 1855, p. 250. A small form of this has been found as far east as Escambia County, Florida. ‘The pseudocardinals are usually split up into radial, nodulous lamellz and are quite different from those of any North American Naiad I know of. Conrad says that his Unio granadensis is suboval, with the disks somewhat flattened, with minute radiating lines extend- ing to the tips of the beaks. He also states that the nacre of his species is purple. The description therefore fits Lamarck’s species perfectly, though I have never known the species to come from so far west as the Rio Grande, Conrad’s locality. Genus OBOVARIA Rafinesque, 1810. Obovaria RAFINESQUE, J. de Phys. Chim. Hist. Nat., 1819, p. 426.—OrTMANN, Ann. Car. Mus., VIII, 1912, p. 320. Shell short, oval, rounded or retuse, solid, inflated, thick in front, thinner behind, with high beaks, which are sculptured very faint, irregular, often broken and_ slightly nodulous ridges, which show a tendency to fall into two loops, the pos- terior often open behind; epidermis dull, brownish, silky, or cloth-like, rarely rayed, rays indistinct; female shell but slightly inflated in the post-basal region, commonly having a shallow furrow or a flattened area at the posterior end ; pseudo- cardinals solid, stumpy; laterals short, club-shaped: anterior and posterior cicatrices deep and distinct; nacre bluish-white or purple. Animal having the gills very short, the inner united to the abdominal sac throughout; marsupium projecting far below the rest of the branchiz and occupying the posterior portion of the outer gills, dolabriform or kidney-shaped; mantle with a wide, thickened, double-edged border, the inner edge of which is often slightly toothed at its posterior part. Type, Unio retusa Lamarck. The genus Obovaria, as I have defined it, consists of a few species belonging to the Mississippi and Gulf drainage. The shells are short, rounded or elliptical, solid and inflated 290 OBOVARIA that of the male and female being generally slightly differenti- ated. The female has a highly organized marsupium much like that of Lampsilis. Unio ellipsis of Lea and its ally U. castaneus differ much in shell characters from the typical Obovarias and form a group that is certainly worthy of subgeneric rank. Kry TO THE SPECIES OF OBOVARIA. Shell nearly or quite equilateral. Beaks very high and curved forward. O. retusa. Short, inflated, dull colored, decidedly lighter behind. O. circulus. Subcompressed to subinflated, smoky, subshining. — O. lens. Rather bright, more or less rayed. O. unicolor. Small, yellowish, or with a brown flush. O. letbit. bovate, small. O. nux. Nearly orbicular, blackish. O. rotulata. Shell decidedly inequilateral. Beaks subterminal, umbonal region inflated. Rather large, not dark colored. O. ellipsis. Small, dark colored. O. castanea. Beaks subcentral, umbonal region subcompressed. O. jacksoniana. Subgenus OROvARIA &. Ss. Shell retrose to short oval: beaks high, central; pseudocar- dinals rarely parallel with the laterals; cavity of the beaks deep, subcompressed: nacre bluish-white or purple. Animal with the characters of the genus. OBOVARIA RETUSA (Lamarck). Shell irregularly quadrate, solid, inflated, with very high beaks, which are turned most decidedly forward over a well- defined lunule; nearly straight or somewhat rounded at the dorsal line, subtruncate behind, curved or nearly straight at the base; posterior ridge rather high and rounded; surface sculptured with low, wide and irregular concentric ridges ; epidermis yellowish-brown, somewhat cloth-like in fresh speci- OBOVARIA 291 <= mens, rayless; left valve with two stout subradial pseudo- cardinals, with two short, curved laterals, the lower sometimes double ; right valve with three pseudocardinals, the middle the larger, the hinder parallel with the somewhat double lateral ; hinge plate flat, sharply curved in front of the laterals; beak cavities deep, compressed, the dorsal scars under the pseudo- cardinals; muscle scars deep, small; nacre coppery-purple, that of the female thickened in front. Female shell with a decided groove behind the posterior ridge, the marsupial area slightly produced. Length (male) 50, height 50, diam. 32 mm. Length (female) 47, height 53, diam, diam. 35 mm. Ohio, Cumberland, and Tennessee River systems. Type locality, “les rivieres de la Nouvelle Ecosse.” Umio retusa LAMARCK, An. sans Vert., VI, 1819, p. 72. Unio retusus Conrap, Monog., II, 1836, p. 19, pl. vitt—Re«EvE, Conch. Syst., I, 1841, p. 118, pl. n.xxxvu, fig. 16—Hantery, Biv. Shells, 1843, p. 202, pl. xxi, fig. 11.—Kusver, Conch. Cab. Unio, 1852, p. 58, pl. xi, fig. 2—Sowersy, Conch. Icon ee Vl SOS, pl: EXT he. .263-— Carr, Wr, Acad. sei. St. Louis, VIL. 1895, p. 45, pl. vit. Margarita (Unio) retusus Lea, Syn., 1836, p. 34. 1628, po 23. Margaron (Unio) retusus Lea, Syn., 1852, p. 35; 1870, p. 56. Obovaria retusa Simpson, Syn., 1900, p. 599.—ORTMANN, Ann Car. Mise, V Uhl oon, ip 321, figs zo: Unio torsus Poriez and Micuaup, Gall. Moll., 1844, p. 149, pli avin, figs! ir, 2. A most remarkable shell, the beaks in old specimens being very high and curved forward like those of an /socardia. OBOVARIA CIRCULUS (Lea). Shell variable in outline, subtriangular, rounded or short elliptical, solid, inflated, with high beaks, which are often somewhat turned forward over a moderate lunule, their sculp- ture consisting of a few rather feeble, slightly doubly-looped ridges; posterior ridge low, rather rounded; surface smooth or having few low, irregular, wide, concentric ridges, covered 292 OBOVARIA with a rayless, dusky brown, often cloth-like epidermis, which is much lighter colored on the posterior slope; left valve with two stout, radial pseudocardinals and two short, nearly straight laterals; right valve with three pseudocardinals, the middle one strong, the hinder faint and sometimes wanting ; beak cavities shallow or only moderately deep, compressed ; dorsal scars under the pseudocardinals; nacre silvery white, pink, salmon, rich purple. length 45, height 47, diam. 30 mm. Length 48, height 46, diam. 28 mm. Length 58, height 55, diam. 42 mm. Ohio, Tennessee and Cumberland River systems; southeast Louisiana and Tombigbee drainage. Reported from Mich- igan and the St. Lawrence drainage. Type locality, the Ohio at Cincinnati, the Monongahela at Pittsburgh and the Tennessee at Nashville. Unio circulus Lea, Tr. Am. Phil. Soc., III, 1829, p. 433. pl. Ix, fig. 14; Obs., I, 1834, p. 47, pl. rx, fig. 14—HAN Ley, Biv. Shells, 1843, p. 201, pl. xx, fig. 23——Kuster, Conch. Cab. Unio, 1852, p. 41, pl. vu, fig. 2—CuHENu, Ill. Conch., 1858, pl. xvi, figs. 1, 1a, 1b—ReEveE, Conch. Icon., XVI, 1865, pl. xxvui, fig. 135. Margarita (Unio) circulus Lea, Syn., 1836, p. 33; 1838, p. 22. Margaron (Unio) circulus Lea, Syn., 1852, p. 343 1870, p. 55- Obovaria circulus SIMPSON, Syn., 1900, p. 600. Unio subrotundus Frrussac, part, Guer. Mag., 1835, p. 28. Unio subrotundus Raf. v. circulus Pavret, Conch. Sam., III, 1890, p. 168. Mya rotunda Woop, Index Test. (Rev.), 1856, p. 199, pl. 1, Supp., fig. 1. A remarkably variable and unsatisfactory species. Speci- mens on the one hand almost run into retusa and on the other hand there seems to be a more or less complete blending into lens. Generally it is smaller and more inflated than the latter species. The epidermis of circulus on the body of the shell is dark and absolutely lusterless; that of Jens is lighter colored and of a more nearly uniform color, and often faintly shining, OBOVARIA 293 The female shell is very little more produced in the marsupial region than the male and the difference between male and fe- male shells in this species is less than in O. lens. OPpOVARIA LENS (Lea). Shell suborbicular, equilateral, subcompressed to subinflated, with rather high, but not inflated, beaks; beak sculpture fine, doubly-looped ridges; posterior ridge rounded; posterior end subtruncate; surface often with a few wide, low, concentric ridges ; epidermis brownish, silky, lighter on the posterior slope ; left valve with two subradial pseudocardinals, and two laterals ; right valve with three pseudocardinals, the middle one largest, and one somewhat double lateral; beak cavities rather deep, compressed; muscle scars small, impressed; nacre white or silvery. ‘The female shell is slightly fuller than the male just behind the center of the base. Length 50, height 47, diam. 26 mm. Ohio River Drainage; north to Lake Erie; southern Michi- gan; south to Columbus, Mississippi. Type locality, Ohio and Tennessee. Unio lens Lea, Tr. Am. Phil. Soc. Phila., IV, 1831, p. 80, pl. vil, fig. 10; Obs., I, 1834, p: 90, pl. vim, fig. 10.—HANLEy, Biv. Shells, 1843, p. 201, pl. xx1, fig. 4—CueENu, Ill. Conch., 1856, pl. vit, figs. 10, 10a, 10b.— Reeve, Conch. Icon., XVI, 1865, pl. XxvI, fig. 134.—SoweErpy, Conch. Icon., XVI, 1866, pl. xxxvu, fig. 200. Margarita (Unio) lens Lea, Syn., 1836, p. 33; 1838, p. 22. Margaron (Unio) lens Lea, Syn., 1852, p. 34; 1870, p. 55. Obowaria lens Stmpson, Syn., 1900, p. 600. ? Unio levigatus Say, Am. Conch., VI, 1834. Var. depygis (Conrad). Shell having the beaks slightly nearer to the posterior end; anterior end somewhat narrowed ; posterior end not lighter col- ored. Type locality, Harpeth River, Tennessee. 294 OROV ARTA Unio depygis CONRAD, Am. Jl. Conch., II, 1866, p. 107, pl x. fig. I. Obowaria lens var. depygis SIMPSON, Syn., 1900, p. 601. Var. parva n. v. Shell very much smaller than the type, varying from sub- solid to moderately solid, subinflated to inflated; nacre white or rose-tinted. The female shells are shorter than the males, wider behind, and have a decided post-basal swelling, with a shallow, wide, radial furrow above it. Length (male) 32, height 25, diam. 15 mm. Length (female) 29, height 27, diam. 17 mm. Maumee and Wabash Rivers; Sandusky, Ohio; Tennessee. This shell has much the same coloring and general form as O. lens, but is exceedingly dwarfed. A specimen from the Amite River, Clinton, Louisiana, may possibly be referred to this. It is more inflated and is more regularly rounded than other specimens of the variety. One shell of the variety has pink-tinted nacre. Var. elongata n. v. _ There is a form found in the Ohio River, which is more elongated and inflated than the type, and has the beaks nearer to the anterior end, which may bear the above name. Length, 67, height 53, diam. 35 mm. This is, if a good species at all, an exceedingly puzzling and variable one. On the one hand it seems to almost insensibly merge into ©. circulus and by many good conchologists it 1s thought to equal that species, while on the other it is with difficulty separated from O. unicolor. It is usually entirely rayless and is duller colored than the latter. Specimens with a pink or purplish nacre, which I formerly referred to this species are, I believe, O. unicolor. The variety elongata is dis- tinct enough to be a valid species, but I hardly feel qualified, with the small amount of material I have seen, to give it more than varietal rank. Conrad’s depygis differs in being inequi- OBOVARIA 295 lateral, with the remarkable character of the beaks nearest the posterior end, that end being the same color as the rest of the shell. OBOVARIA UNICOLOR (Lea). Shell short elliptical or ovate, subinflated, rather solid, with a low, but distinctly marked, somewhat rounded posterior ridge; beaks rather full and high, in front of the middle, with feeble, imperfectly looped ridges ; surface nearly smooth, some- what sulcate on the anterior end; epidermis yellowish-brown or brownish, shining, often distinctly, though not brilliantly rayed, in the young shell greenish, lighter in front and having green rays; left valve with two radial pseudocardinals and two curved laterals; right valve with three pseudocardinals, the central one much the larger, and a somewhat double lat- eral; beak cavities not deep, rather compressed; muscle scars small impressed; nacre usually pinkish, but sometimes white or bluish. Length 50, height 43, diam. 26 mm. Mississippi and Alabama, in streams flowing into the Gulf. Tvpe locality, Tuscaloosa, Ala. Unio wmcolor Lua, Pr. Am. Phil. Soc., 1V, 1845, p. 163; Tr. Am. Phil. Soc., X, 1848, p. 74, pl. iv, fig. 12; Obs., IV, 1848, p: 48, pl. rv, fig. 12: Margaron (Unio) umcolor Lea, Syn., 1852, p. 34; 1870, p. 55. Obovaria unicolor SIMPSON, Syn., 1900, p. 601. Unio tinkeri B. H. Wricut, Nautilus, XIII, 1899, p. 7. Obovaria tmkeri Simpson, Pr. Acad. Nat. Sci. Phila., rgoo, p. 78, pl. IV, fig. 3; Syn., 1900, p. 500. The type of this species, which is a young female, is some- what broken and there is another shell in Lea’s collection from Jackson, Mississippi, which he has called Unio lens, that is a young male. The name unicolor is rather infelicitous, as it is the only rayed species in the group. These rays and its gener- ally bright color are the best characters by which to distinguish it from allied species. The female shell is a little more inflated at the posterior base than that of the male. I have seen speci- 296 OBOVARIA mens of what I believe to be genuine O. lens from Columbus, Mississippi. After carefully comparing the Unio tinkeri B. H. Wright with numerous specimens of unicolor, | am forced to the conclusion that the two are practically the same. I have recently had an opportunity of examining quite a good series of these shells. OpovaRiA LEIBII (Lea). Shell small, only moderately solid, inflated, oval or short ellip- tical: beaks rather full in front of the middle, their sculpture not seen; posterior ridge low, somewhat rounded ; surface with low, irregular concentric ridges; epidermis generally yellowish or dirty yellowish-green, sometimes of a uniform brownish color in the lighter specimens, not so dark behind in the brown shells; left valve with two small, subtriangular pseudocardi- nals and two laterals; right valve generally with three pseudo- cardinals, the middle one only prominent and one lateral ; beak cavities not deep; muscle scars shallow: nacre whitish. The female shell is produced somewhat at the post-base, and above and behind the swelling there is often a shallow, wide, radial furrow such as is seen occasionally in the allied species. Length 35, height 22, diam. 18 mm. Length 32, height 29, diam. 20 mm. Length 28, height 24, diam. 18 mm. Lake Erie and streams falling into it; southern Michigan. Type locality, Erie County, Michigan. Umio leibt Lea, Proc. Acad. Nat. Sci. Phila., VI, 1862, p. 168; JL Ac. N. Sct. Phila, Vi.» 1866, p..44, pk sap ae ao Giese XI, (1867, p. 48, pl..xv, hewe: Margaron (Unio) leibti Lma, Syn., 1870, p. 36. Obovaria leibii SIMPSON, Syn., 1900, p. 601. I am inclined now to believe this is a valid species, certainly as good as most of those of this puzzling group. It is always small and longer than high, it is comparatively thin, and its female shells are more produced in the marsupial region than those of O. circulus. The specimen from the Sequatchee River, Tennessee, and others that I have seen from Tennessee OBOVARIA 297 since writing the Synopsis are probably not this, but more likely the dwarf form of O. lens that I have called war. parva. OBAVARIA NUX DN. S. Shell rather small, greatly inflated, obovate, solid, consid- erably narrowed and rounded in front, wider and subtruncate behind ; beaks no doubt full and high, but greatly eroded in the only shells seen, placed well towards the anterior end; poste- rior ridge moderate and above it is a shallow, wide radial de- pression ; base line rounded, quite full behind the middle; sur- face with a few feeble ridges, otherwise smooth; epidermis a rich chestnut, very much lighter colored posteriorly and at the base of the shell; left valve with two triangular pseudocar- dinals and two remote, short, curved laterals, the high arched hinge line narrowed and rounded between the two sets of teeth; right valve with one strong pseudocardinal, a vestigial tooth each side of it and one somewhat double lateral ; beak cavities rather shallow ; dorsal scars showing in a row under the pseu- docardinals; muscle scars small, impressed; nacre whitish. The only specimens seen probably females, having a sulcus behind, such as is found in O. leibii, and a rather full marsu- pial region. Length 40, height 30, diam. 25 mm. Tombigbee River, Moscow, Ala; Cannisaria Lake, Louis- jana. I am exceedingly loath to name a species in this especially difficult group from a couple of specimens, yet the shells I have described will not fit anywhere. The species is perhaps nearest to O. leibii, but it is solider, darker and smoother than that. The smaller of the two shells before me, from Canni- saria Lake. Louisiana, is a female and agrees in all essential characters with the larger shell from the Tombigbee River. OBOVARIA ROTULATA (B. H. Wright). Shell almost circular in outline, solid, inflated, probably hav- ing high beaks, which are badly and deeply eroded in the type, with a faint, curved posterior ridge and a small, somewhat 298 OBOVARIA cordlike ridge above it; surface with a few, low, concentric ridges, otherwise nearly smooth ; epidermis deep brown, nearly black, a little lighter colored at the anterior end; left valve with two low, broad, not very perfect, pseudocardinals and two short, curved laterals; right valve with one pseudocardinal, a feeble tooth above, and a wide roughened area behind it, with one somewhat double lateral; beak cavities very deep, com- pressed ; anterior muscle scars roughened; nacre dirty white, slightly iridescent behind. Length 40, height to top of eroded beaks 45, diam. 30 mm. Type locality, Escambia River, Escambia County, Florida. Unio rotulatus B. H. Wricur, Naut., XIII, 1899, p. 22. Ohovaria rotulata Simpson, Pr. Ac. N. Sci. Phila., 1900, p. 93, pl. iv, fig. 2; Syn, 1900; p: 608: [ have only seen a single specimen of this, the type, which seems to be one of the best marked species of the genus. Its color pattern 1s quite different from that of circulus and allied forms, and its low, irregular, broad pseudocardinals and the remarkably deep, compressed beak cavities serve to distinguish it. Subgenus PskEuDOON Simpson, 1900. Pseudoon SIMPSON, Syn., 1900, p. 601. Shell elliptical, inflated, solid, that of the males slightly pointed at the upper posterior part; epidermis brownish or blackish, rayless or very feebly rayed; beaks anterior ; pseudo- cardinals solid, stumpy, or slightly elongate in age, and show- ing a tendency toward being parallel with the laterals; cica- trices deep; nacre silvery, iridescent posteriorly. Animal having a mantle with a wide, thickened, double bor- der, the inner edge being toothed throughout below; gills small; marsupium not reaching to the posterior end of outer branchiz, though extending quite well forward; ovisacs rather numerous, large and distinct, tinted with purple below; anal and branchial openings finely toothed. Type, Unio ellipsis Lea. OBOVARTA 299 OsovVARIA ELLIPSIS (Lea). Shell usually evenly elliptical, sometimes rather ovate, in- flated, solid, with high beaks placed close to the anterior end and turned forward over a small lunule, their sculpture con- sisting of a few somewhat doubly looped bars ; posterior ridge scarcely developed ; anterior end rounded or subtruncate ; sur- face nearly smooth or having a few shallow, irregular sulca- tions; epidermis greenish or yellowish-brown, with faint, darker rays; left valve with two pseudocardinals, the posterior one nearly parallel with the stout, curved laterals; right valve usually with three pseudocardinals, the two outer ones small, the middle and upper ones in all shells parallel with the strong double lateral: beak cavities shallow, showing a row of dorsal scars; muscle scars small, impressed, the anterior ones rough; nacre silvery white, much thickened in front. The shells ot the male and female differ but little, those of the latter being a very little more produced at the post-basal part than the former. Length 75, height 56, diam. 45 mm. Length 63, height 47, diam. 35 mm. Upper Mississippi system as far south as the Tennessee and Arkansas Rivers; St. Lawrence drainage area. ‘Type locality, Ohio. ? Unio brevialis Sowerby, Rec. and Foss. Shells, XVI, 1823, he. Unio ellipsis Lua, Tr. Am. Phil. Soc., HI, 1828, p. 268, pl. Iv, he 49 Obs., 1824: 4p: ro; pli iv, fig: 4 Say. An. Conch, I, 1831, pl. x1v—Han ey, Biv. Shells, 1843, p. 188, pl. XX1, fic. 7—Potirz and Micnaup, Gall. Moll., 1844, p. 150, pl. 22, pl. 1v, figs. 1, 1a, 1.—Kusrter, Conch. Cab. Unio, 1852, p. 43, pl. vin, fig. 4—CHENU, Ill. Conch., 1858, pl. Xvi, figs. 1, ta, 1b—Sowersy, Conch. [con., XVI, 1868, pl. LXXX, fig. 424. Margarita (Unio) ellipsis Lea, Syn., 1826) p. 22,1838) "p. 1s: 300 OPOVARIA Margaron (Unio) ellipsis Lea, Syn., 1852, p. 26; 1870, p. 41. Obovaria ellipsis SIMPSON, Syn., 1900, p. 602. Unio triangularis SAy, Am. Conch., VI, 1834. Umo olivarius Conran, New F. W. Shells, 1834, p. 70. Unio taitianus Sowerby, Conch. Icon., XVI, 1868, pl. Lxvu, fig. 338. Unto pealet Lea, Pr. Ac. N. Sei. Phila., I, 1871, p. 191; Jl.-Ac. N. Set. Phila.; VIL, 1874; p. 26, pl. viii tie, 235 'Ohs. IT, 1874, p. 30, pl. viii, fig. 23. Unio pealei Lea, of Kansas, is a little lighter colored than the type and has the beaks a little farther from the anterior end, but it does not seem to me to be worthy of even varietal rank. OBOVARIA CASTANEA. (Lea). Shell rather small, that of the male ovate, that of the female elliptical, inflated, solid, blackish-chestnut or olive-green, some- times with faint, concentric, lighter and darker bands, occa- sionally faintly rayed behind; beaks full and high, placed near the anterior end and marked with a few feeble, nearly parallel ridges; posterior ridge low; left valve with two pseudocardi- nals, the upper running nearly parallel with the two curved laterals; right valve with two pseudocardinals, with rarely a third posterior one, the anterior tooth compressed, and a double lateral; beak cavities shallow; muscle.scars small, impressed ; nacre whitish or bluish white, iridescent and slightly thinner behind. The male shell is ovate and pointed behind about mid- way up from the base; the female shell is elliptical, full at the post-base, scarcely pointed behind, and in all cases I have seen is much smaller than that of the male. Length (male) 40, height 32, diam. 27 mm. Length (female) 28, height 22, diam. 20 mm. Streams flowing into the Gulf of Mexico, from the Alabama River west to the Nechez. Type locality, Alabama River. OBOVARIA 301 Unio castaneus Lea, Tr. Am. Phil. Soc., IV, 1831, p. 91, pl. x1, fig, 21; Obs., I, 1834, p. 101, pl. x1, fig. 21—HANLey, Biv. Shells, 1843, p. 188, pl. xx11, fig. 30—CueENu, Ill. Conch., 1858, pl. x1, figs. 5, 5a, 50. Margarita (Unio) castaneus Lea, Syn., 1836, p. 22 ; 1838, p. 18. Margaron (Unio) cestaneus Lea. Syn., 1852, p. 26; 1870, p. 41, Obovaria castanea SIMPSON, Syn., 1900, p. 602. Much smaller and darker than ellipsis, and the difference between male and female shells is much more strongly marked. Some of the male shells approach closely to Lea’s Unio simu- lans, but are generally a little heavier and more inflated. In the latter species the male and female shells are essentially alike. The name castaneuws was applied to some Unio, which I am unable to determine, by Rafinesque in a Continuation of a Mon- ograph on the Bivalve Shells of the River Ohio, etc., in Octo- ber, 1831. According to Scudder, Lea’s name was published the latter part of the same year, but I have no means of knowing which appeared first. Under the circumstances I use Lea’s name. OBOVARIA JACKSONIANA Frierson. “Shell ovate, smooth, rounded before and below, nearly straight from beak to post-point, which is about half way the height of the shell; umbonal ridge low, and the posterior area very narrow ; beaks not high, sculpture not seen; nacre bluish- white, iridescent behind; teeth double in left, single in right valve; cardinals stout, erect; laterals not very large; muscle scars confluent behind, separate before; pallial line obsolete behind. Length 45, height 33, diam. 20 mm.” (Frierson). Type locality, Pearl River, Mississippi. Also in the Yala- busha River, Mississippi. Unio (Obovaria) jacksonianus Frierson, Naut. XXVI, 1912, Breeze, hy trees: 1,2 Bs ae “The novelty of the present species was determined by gra- vid specimens collected by Mr. A. A. Hinkley and by a com- parison with castaneus of the Lea collection by Mr. Bryant 302 PLAGIOLA Walker. This species has not the female form of castaneus, and the dorsal scars are in the bottom of the beaks in place of being on the teeth. In outline it is nearly the same as U. strodeanus B. H. Wr.. but differs in being greenish, while strodeanus is dead black : its beak cavities are deeper, and its teeth are much longer, stouter and more erect. From U. curtus, to which it is allied, it differs, lacking the pronounced swelling before. Many of these shells show a constriction like the U. con- strictus of Conrad, and it may be that this is a sexual mark.” The following species are unfigured or indeterminable. Obovaria cordata RAFINESOQUE, Ann. Gen. Sci. Brux., V, 1820, Poste: Pl. LET, fos. oO. 7 Obowaria stegaria RAFINESQUE, Ann. Gen. Sci. Brux., V, 1820, P32; pl. Lee, esas Obovaria striata RAFINESQUE, Ann. Gen. Sci. Brux., V, 1820. D. Sia Obovaria torsa RAFINrSQUE, Ann. Gen. Sci. Brux., V, 1820, Pp. 312, pl UAkKM, fies hy 2: Obliquaria retusa RAFINESQUE, Ann. Gen Sci. Brux., V, 1820, p. 206; ‘pl. LxkxI, figs. 10,;20: Genus PLAGIOLA (Rafinesque, 1819) Agassiz. Plagiola RAFINESQUE, J. de Phys. Chim. Hist. Nat., 1819, p. 426.—Acassiz, Arch! fur Nat., 1852, p. 48, redefined. OrtTMANN, Ann. Car. Mus., VIII, 1912, p. 329. Shell triangular ovate, somewhat inflated, solid, with a dis- tinct and often sharp posterior ridge; surface concentrically sculptured ; umbonal area somewhat flattened ; beaks high but compressed, sculptured with delicate, parallel, doubly-looped ridges, the anterior loop rounded, the posterior angular ; pseu- docardinals ragged; laterals club-shaped, straight or slightly curved; cavity of the beaks moderate, often somewhat com- pressed: nacre silvery: female shell more or less inflated at post-basal region. PIAGIOLA 303 Animal having the outer gills narrow in front and wide behind; inner gills wide in front, posteriorly free or united to abdominal sac ; marsupium occupying the posterior part of the outer gills, but not extending quite to the hinder end, consist- ing of well-marked ovisacs, which are rounded below; a dis- tinct sulcus extends the whole length of the kidney-shaped marsupium at the inside and outside at some distance above its base ; mantle edge thickened and somewhat doubled, in some cases toothed or fringed below. Type, Unio securis Lea. The genus Plagiola, as I have constituted it, contains a small number of North American species having rather short, triangular-ovate shells with high, but mostly compressed, beaks and a strong, usually rather sharp, posterior ridge. In gen- eral the female shell has a more or less distinctly developed marsupial swelling. The marsupium is much like that of Lampsilis and the higher organized Naiades consisting of dis- tinctly marked ovisacs in the hinder part of the outer gills. The genus is easily divisible into three well-marked sub- genera, the typical Plagiola with a heavy shell, with highly painted epidermis and wide hinge plate, the female shell being smaller and more inflated than the male, and having a well-developed marsupial swelling; Amygdalonaias with much more delicate, highly pointed shells with a narrow hinge plate, and Artonaias, a group of Central American forms, with concentric sculpture and full colored, often wrinkled, epider- mis. It may be remarked that occasional specimens in beth the first mentioned subgenera are dull colored, destitute of rays and have slightly wrinkled epidermis. Key TO SPECIES OF PLAGIOT,A. Shell painted with broken rays. Heavy, with wide hinge plate. P. securis: Subsolid, with narrow hinge plate. Inflated, strongly truncated behind. P. elegans. Moderately inflated, rather solid. P. cognata. Scarcely inflated. P. donaciformis. Compressed. P. macrodon. 304 PLAGIOLA Shell dull colored, sulcate. Surface radiately grooved. Rather solid, tawny or pale brown. P. cyrenoides. Subsolid, dark colored. P. imbricata Surface not radiately grooved. Very solid, greatly inflated. P. salle. Subsolid, moderately inflated. P. nicaraguensis. Subgenus PLAGIOLA Ss. S. Shell solid, surface irregularly concentrically ridged; epi- dermis smoothish, but here and there wrinkled; painted with larger and smaller scattered rays, which are generally broken into irregular lunate or squarish blotches; hinge heavy and strong; hinge plate wide and flat ; female shell smaller than the male, more inflated, and swollen at post-basal region. Animal having the branchiz rounded below, inner the larger, wholly or partly free from the abdominal sac; marsupium large, projecting far below the inner gills; mantle very thin, dark on its thickened, fringed double edge; anal opening with very small papillee. PLAGIOI,A SECURIS (Lea). Shell subtriangular, solid, subcompressed or scarcely inflat- ed, with a sharply defined up-curved posterior ridge, behind which it is truncated; region of the beaks and a considerable area of the upper part of the shell compressed; beak sculp- ture consisting of a few irregular, slightly doubly-looped ridges; beaks curved forward over a small, wide lunule pass- ing back under the hinge, where it is filled with epidermal matter; ligament small, brown; surface with irregular, often rude, sometimes almost sulcate, growth lines; epidermis rather smooth, but showing fine, wrinkled loops under a glass, tawny or yellowish-green, generally with faint, broken rays, which are made up of dots or lunate or arrow-head markings ; they are sometimes composed of alternately lighter and darker dashes; hinge strong, the plate often flattened ; left valve with two trianeular, ragged pseudocardinals, a faint anterior third PLAGIOLA 305 one, and two slightly curved laterals; right valve with three pseudocardinals, the middle one the largest, and two laterals, the lower the smaller; beak cavities moderately deep; muscle scars impressed, the anterior ones ragged; nacre silvery-white The male and female shells differ widely, the former are much the larger and are considerably compressed; the female shell is somewhat humped, is more or less inflated, is considerably produced at the posterior base and gaps a little in front and behind. Length (male) 90, height 66, diam. 35 mm. Length (female) 57, height 43, diam. 30 mm. Mississippi drainage south into Arkansas; west into eastern Iowa and Kansas; Tombigbee and Alabama river systems. Type locality, Ohio. Obliquaria (Plagiola) depressa RAFINESQUE, Ann. Gen. Sct. Phys. bri. 1520) p. 402, pl. xxx, figs. 5-7. Unio securis Lea, Tr. Am. Phil. Soc., III, 1820, p. 437, pl. x1, foe Obs. 1634. p51, pl. Xi le: 17-—TANt Ey, Biv. Shells, 1843, p. 184, pl. xx, fig. 51.—CuHenu, Ill. Conch., 1858, pl. xvt, figs. 4, 4a, 4b; Man., II, 1859, p. 138, fig. 671. =SoweErsy, Conch. Icon., XVI, 1868, pl. Lx1, fig. 304. Margarita (Unio) securis LeA, Syn., 1836, p. 19; 1838, p. 16. Margaron (Unio) securis Lea, Syn., 1852, p. 24; 1870, p. 37. Plagiola securis SmrrH, Bull. U. S. Fish Com., 1899, p. 291, pl. LXXX.—SIMPSON, Syn., 1900, p. 603. Unio lineolata Say, Am. Conch., VI, 1834. Plagiola lineolata Acassiz, Arch. fiir Nat., I, 1852, p. 48. Unico lineolatus Conran, New F. W. Shells, 1834, p. 70.—SAy, Am. Conch. (continuation), VII, pl. Lxvirr (no date).— Kkrster, Conch. Cab. Unio, 1861, p: 171, pl. Lil, figs. 1, 2. In some cases the female shell differs so from that of the male that expert students have believed it to he a different species. I have an apparently fully adult female shell before me, which is 40 millimeters long, 36 in height and 25 in diam- eter. The males appear to be most abundant. Some Coosa River specimens have a rough, rayless epidermis with more or less wrinkled loops. They are destitute of any pattern of 306 PJLAGIOLA painting and to some extent resemble such Central American specimens as P. cyrenoides and imbricato. Rafinesque’s name depressa. for what is probably a male of this species, has precedence over Lea’s name, but it was used previously by Lamarck for an Australian Unio. Rafinesque placed this species in his genus Obliquaria and the subgenus Plagiola, but after giving the name Obliquaria depressa he called it U. depressa in parenthesis. Subgenus AMyGDALONAIAS Fischer and Crosse. 1893. Amygdalonaias FiscHER and Crosse, Miss. Scient. Mex., Moll., II,- 1893; p: 557- Amygdalonajas ORTMANN, Ann. Car. Mus., VIII, 1912, p. 327. Shell compressed to inflated, decidedly truncated at the pos- terior slope; surface slightly concentrically sculptured ; poste- rior ridge sharp and well defined; epidermis shining, some- times wrinkled, looped and painted with a beautiful pattern of broken or arrow-headed rays; area of the beaks flattened off in the direction of the axis of the shell, but not compressed ; beak sculpture delicate, somewhat broken and doubly-looped, the anterior loop rounded, the posterior sharp below, the ribs fading out where they cross the posterior ridge ; hinge delicate ; pseudocardinals rather compressed, high and ragged; hinge plate narrow; female shell very slightly swollen at post-base. Animal having the branchiz more or less free from the abdominal sac; marsupium consisting of numerous distinct ovisacs and having a well-marked sulcus extending around it at some distance above its base; mantle thickened and doubled on its edge, which has dark papille. Type, Unio cognatus Lea. Ortmann, (1. c.), raises this group to generic rank. Group of Plagiola elegans. Shell short, triangular oval, inflated with a very sharp pos- terior ridge extending from the beaks to the hinder point of the shell; male and female shells scarcely distinguishable, both being much expanded in the basal region. PLAGIOLA 307 PILAGIOLA ELEGANS (Lea). Shell subrhomboid, solid, inflated, with a very sharp pos- terior ridge, behind which it is decidedly truncated; beaks high and full, turned forward over a small lunule; region of the beaks and upper part of the shell decidedly flattened; central base of the shell full; posterior point sharp, elevated considerably above the base; surface with irregular, subsul- cate growth lines; epidermis dull or somewhat shining, often having wrinkled loops behind, yellowish-green with numerous wavy, often broken, rays. Sometimes in addition to the rays there are numerous wavy or zigzag lines and occasionally the shell is tawny or reddish and rayless ; hinge line curved ; pseu- docardinals ragged, two in the right valve and one in the left, sometimes they are much split up; left valve with two laterals: right valve with one and sometimes a faint second one below it; beak cavities not deep; muscle scars impressed ; nacre bluish-white, white, salmon or reddish. The form of the shell is quite variable and those of the female and male differ put little from each other. The female shell is a little more pro- duced at the central base. Length (male) 57, height 43, diam 30 mm. Length (female) 68, height 52, diam. 37 mm. Mississippi drainage generally; Michigan; Lake Michigan ; southwest to Trinity River, Texas. Type locality, Ohio River. . Unio elegans Lea, Tr. Am. Phil. Soc., IV, 1831, p. 83, pl. cx, fig. 13; Obs., I, 1834, p. 93, pl. 1x, fig. 13:— Han ery, Biv, shells, 1843, p. 183, pl. xx1, fig. 33.— CHEN, Ill. Conch. 1858, pl. xv, figs. 3, 3a, 3b; Manual, II, 1859, p. 138, fig. 672. — Sowersy, Conch. Icon., XVI, 1868, pl. Lxxiv, p. 380. Margarita (Unio) elegans Lea, Syn., 1836, p. 18; 1838, p. 16. Margaron (Unio) elegans Lua, Syn., 1852. p. 23; 1870, p. 36. Plagiola elegans BAKER, Moll. Chicago, Pt. 1, 1808, p. or, pl. XXI, fig. 1—Srmpson, Syn., 1900, p. 604. Amvygdalonajas elegans OrtMANN, Ann. Car. Mus., VIII, LOE2: px, 326. 308 PLAGIOLA Unio truncatus Say, Am. Conch., VI, 1834; Am. Conch. (cun- tinuation), VII, pl. nxvir (no date).—Kusterr, Conch. Cab., TSOl; p>. 174, pl Ly, fips 23: Unio truncatus RAFINESOUEK var. elegans Pa:reL, Conch. sam., III; 1890;‘p. £70. Shorter, more inflated and more decidedly truncated behmd than P?. donaciformis, towards which it sometimes varies. Group of Plagiola donaciformis. Shell small, elongated, triangular oval; posterior ridge generally well defined but rarely sharp, having broken green rays, which form chevrons or blotches on a lighter ground; female shell somewhat inflated in the post-basal region. PLAGIOLA DONACIFORMIS (Lea). Shell rather small, subsolid, irregularly ovate, subinflated, inequilateral, with moderately high and full, though slightly flattened, beaks, whose sculpture consists of fine, doubly-looped ridges, the hinder loop being quite irregular on the sharp pos- terior ridge; surface with irregular growth lines, sometimes slightly plicate or corrugated on the posterior slope, generally shining, pale or yellowish-green with a beautiful pattern of darker green rays. ‘hese rays are sometimes entire, but are generally broken up into arrow-head or zigzag markings; left valve with two compressed pseudocardinals and two laterals ; right valve with one pseudocardinal and one lateral; beak cavities shallow; muscle scars impressed, the posterior ones round; nacre bluish-white. The female shell is apparently always smaller than that of the male and has a decided mar- supial swelling, the sharp posterior point being a little more elevated than that of the male shell. Length (male) 47, height 32, diam. 20 mm. Length (male) 37, height 23, diam. 16 mm. Length (female) 31, height 20, diam. 15 mm. Mississippi drainage generally ; Alabama River area; south- west to the Trinity River, Texas; Michigan. Type locality, Ohio PLAGIOLA 209 Unio donacifornis Les, Tr. Am. Phil. Soc., III, 1828, p. 267, pie mies 3 Obs; 1, 1834,.p.0,.pli mw, fig, 3.-—HANntevy, Big onels. 1543, 5p, des, pl. SKIL fie! 4r—- Cuenu, Ti. Conch., 1858, pl. x1, figs. 4, 4a, 4b. Margarita (Unio) donaciformis Lea, Syn., 1836, p. 18; 1838, PaO: Margaron (Unio) donaciformis Lira, Syn., 1852, p. 24; 1870, p. 30. Plagiola donaciformis Baker, Moll. Chicago, Pt. 1, 1808, pl. xi, fig. 4.— Simpson, Syn., 1900, p. 605. Unio zigzag Lea, Tr. Am. Phil. Soc., III, 1820, p.-440, pl. x11, fey io 1Ops., I. 1534. p54, pl. xi, fie: 19—— HANEY, Biv: Shells, 1843, p. 183, pl. xxi, fig. 42.— Kuster, Conch. Cab. Unio, 1852, p. 42, pl. vin, fig. 3.— CHeEnu, Ill. Conch., 1858, plyvnm, fies.°S,"Sa,-86; Man: 1850,. 1) py 138, fig.-670— Sowrrsy, Conch. Icon., XVI, 1866, pl. xxxrx, fig. 213. Margarita (Unio) sigsag Lea, Syn., 1836, p. 18; 1838, p. 16. Margaron (Umo) zigzag Lea, Syn., 1852, p. 24; 1870, p. 36. Unio nervosa Conrap, New F. W. Shells, 1834, p. 70. Unio nervosus Say, Am. Conch., VI, 1834 Kusrer, Conch. CaboU nto; 1865; py 175; pl.. By; hiss4. A beautiful and variable species, occasionally quite abundant. The pattern of coloring varies greatly, there being occasional shells with unbroken rays, which look like a compressed, drawn-out elegans. Rarely the shell is a uniform ashy or dirty vellowish-green as is sometimes the case with that species. It is generally more inflated than P. macrodon, but it is quite probable that it gradually merges into that species in the south- west. I collected at one time in southern Kansas and Indian Territory and many specimens found in that region seem to stand between the two forms. A specimen before me from Cincinnati, Ohio, is very much like P. macrodon, but has a slightly more distinct color pattern. PLAGIOLA MACRODON (Lea). Shell long ovate, subcompressed, subsolid, with scarcely elevated, compressed, flattened beaks, their sculpture consisting of very fine doubly-looped ridges that are sharply angled at 310 PLAGIOLA the pinched-up posterior ridge; surface rather smooth, feebly shining, pale dirty or smoky-greenish, with a pattern of broken rays, which are often made up of irregular blotches or zigzag markings ; this zigzag pattern is sometimes developed between the rays. Left valve with two compressed pseudocardinals and two laterals; right valve with one pseudocardinal and one lateral; beak cavities very shallow; muscle scars small, the hinder circular; nacre bluish. The female shell is quite full in the post-basal region and much more blunt behind than the male. Length (male) 45, height 27, diam. 16 mm. Length (female) 37, height 23, diam. 14 mm. Eastern Texas, northward probably into Kansas. Type locality, Rutersville, Texas. Unio macrodon Lea, Pr. Ac. N. Sei. Phila., III, 1859, p. 154; jl. Ac. N. Sci. Philazy VI, £862,.p.193,) pl. sauvi, sig.y2n2s Obs., IX, 1863, p. 15, pl. xxv1, fig. 262.—?Sowerrsy, Conch. Icon., XVI, 1868, pl. L.xXxxvitl, fig. 437. Margaron (Unio) macrodon L&A, Syn., 1870, p. 37. Plagiola macrodon SiMPSON, Syn., 1900, p. 605. Less inflated and rather longer than P. donaciformis, the color patterns less vivid and generally not quite as sharply pointed behind. ‘lhe female shell especially is quite blunt. PLAGIOLA COGNATA (Lea). Shell elliptical, convex, solid, inequilateral, with a well-de- veloped posterior ridge and high beaks, which are sculptured with a few delicate, doubly-looped bars; epidermis smooth, shining, vellowish-green with a number of darker rays; left valve with two triangular, somewhat ragged, pseudocardinals, the anterior one smaller, and two laterals, the upper the smaller; muscle scars deep: beak cavities moderate and rather shallow, showing the dorsal scars; nacre bluish white or sil- very, iridescent and thinner behind. Length 44, height 28, diam. 20 mm. Rio Salado, New Leon, Mexico. PLAGIOLA 201 Unio cognatus Lea, Pr. Ac. N. Sci. Phila., [V, 1860, p. 306; jie NocirPiilay Vi; 1860;"p: 368, pl. txv; fir. 193; Obs., VIII, 1860, p. 50, Lxv, fig. 193 SowerrBy, Conch. Icon., XVI, 1866, pl. xxxrx, fig. 214. Margaron (Unio) cognatus Lea, Syn., 1870, p. 43. Plagiola cognata SIMPSON, Syn., 1900, p. 606. I have only seen two left valves of this species, one the type, and a young one. Both are quite solid, the younger being perfect enough to show something of the beak sculpture. The older one is probably from a female, as it is rather full in the post-basal region. I should say that the species is closely related to P. macrodon and donaciformis, but it is a heavier shell than either and more inflated than the former. The younger valve shows a decided, sharp posterior ridge, in frunt of which, especially near the beak, the surface is decidedly flattened or almost excavated as in Plagiola elegans. Subgenus ARTONAIAS von Martens, 1900. Artonaias VON Martens, Biol. Cent. Am., Moll., 1900, p. 48o. Ptychoderma SIMPSON, Syn., 1900, p. 606. Shell triangularly ovate or rounded, solid, bluntly angled before, more sharply angular behind, with a tolerably well- marked posterior ridge; surface strongly and irregularly cou- centrically sulcate; beaks small but rather prominent, sculp< tured with fine, irregular, broken ridges, which are somewhat doubly looped, the front loop being larger and more rounded ; epidermis olive to tawny, wrinkled, sometimes having faint rays; pseudocardinals compressed, ragged; hinge plate nar- row ; laterals short, slightly curved, obliquely striated; muscle scars rather shallow, the posterior round; female shell pro- duced in the post-basal region. Animal having the branchiz small, inner united the whole length to the abdominal sac, wider than the outer in front, narrower behind; marsupium occupying the posterior part of the outer gills in from eleven to twenty distinct ovisacs, which are rounded and dark below, the whole having a distinct, par: allel sulcus inside and out near its base; mantle thin, papery, 312 PLAGIOLA with a wide, thickened, double edge, which is sometimes cre- nate; branchial opening large, fringed; anal opening smooth or with only the faintest crenulations. Type, Unio cyrenoides Philippi. The name Ptychoderma was published by me in the Synopsis Oct. 6, 1900; von Martens had published the name 4rtonaias for practically the same group in the Biologia Centrali Ameri- cana in February of the same year, but at the time my name went through the press I had not seen it. Group of Plagiola cvrenoides. Shell generally more or less covered with radiating grooves, which cut up the concentric sculpture into looped wrinkles or nodules, sometimes having the appearance of dried, wrinkled paint, the sculpture extending into the substance of the shell; epidermis usually tawny or yellowish, rarely showing any vestiges of rays: female shell much produced in the post-basal region. PLAGIOLA CYRENOIDES (Philippi). Shell solid, somewhat inflated, subtriangular or subquad- rate, with rather full and quite high beaks, whose sculpture consists of numerous fine, doubly-looped, corrugated ridges, which gradually fade into the regular shell sculpture ; posterior end obliquely truncate above, with a rounded point about mid- way up from the base; posterior ridge well developed; base well rounded; surface sculptured with slightly corrugated, concentric ridges; epidermis uniform tawny, tawny-green or brownish, cut with impressed radial lines, especially behind, often looped, wrinkled and granulous; left valve with two rag- ged pseudocardinals, the anterior one somewhat compressed, and two curved laterals, the lower higher; right valve with two pseudocardinals, the upper feeble and compressed, and one lateral; beak cavities shallow; muscle scars impressed; nacre whitish, often lurid or blotched, thinner behind. Male shell with a decided rounded point behind scarcely midway up from the base, base evenly rounded. Female shell with a PLAGIOLA 313 strong inflation at or behind the middle of the base; posterior point blunt, more elevated than that of the male shell. Length (male) 54, height 43, diam. 28 mm. Length (female) 50, height 43, diam. 26 mm. Length (female) 44, height 41, diam. 32 mm. Nicaragua; Venezuela? A specimen in the U. S. National Museum from the Morelet collection is marked with the latter locality. Unio cyrenoides Put.trri, Zeits, fur Mal:, TV, 1847, p. 93; Abbild., III, 1848, p. 49, pl. v, fig. 1 — Kuster, Conch. Cab. Unio., 1862, p. 285, pl. xcv1, fig. 1. Margaron (Unio) cyrenoides Lea, Syn., 1852, p. 25: 1870, _?P 38. Plagiola cyrenoides SIMPSON, Syn., 1gO0, p. 606. Unio newcombianus Lea, Pr. Ac. N. Sci. Phila., VIII, 1856, Datos HONS .V 1857.0. 32,-pl xxx, ne 27 fv Ac NL Ser Phila., III, 1858, p. 312, pl. xxx, fig. 27— von Marrens Biol Gent Amer, Moll, 1900, p: 497, pl. xxrx, figs. 1, 1 a-b. Margaron (Unio) newcombianus Lea, Syn., 1870) p.- 36: Umno sagrinatus SowERBy, Conch. Icon., XVI, 1868, pl. uxvit, fig. 345. Unis gabbianus, VON Marvens, Biol. Cent. Amer., Moll., 1900, pl xxx, fiss5; 5a-D: More solid and rudely sculptured, lighter colored and short- er than Plagiola imbricata. Von Martens’ figures of Unio gabbianus on plate xxx1x of the Biologia certainly represent a specimen of cyrenoides, though his description applies to gabbianus. In a female P. cyrenoides, which was not gravid, the sulcus near the base of the inside of the marsupium was quite deep, in fact the part above it hung over it in a sort of flap, which would no doubt disappear 1f it was filled with ova. PLAGIOLA IMBRICATA (Morch). Shell subsolid, rather inflated, subovate or subelliptical, with a well-developed posterior ridge; beaks moderately full, their sculpture not seen, but apparently much as in P. cvrenoides, 314 PLAGIOLA surface covered with fine, granulous, concentric ridges; epi- dermis olive or dark olive-brown, having impressed radial lines over its hinder half, between which lines it is often looped; left valve with two subcompressed, ragged pseudo- cardinals and two laterals, the lower higher; right valve with one pseudocardinal, a vestigial second one above it, and one lateral; beak cavities not deep; muscle scars scarcely im- pressed; nacre dull, lurid or lead-color, frequently blotched. Male shell ovate, pointed behind a little above the base; female shell almost elliptical, with a decided marsupial swelling, the posterior point blunt and well elevated. Length 37, height 28, diam. 20 mm. Nicaragua. Unio (Plagiola?) imbricatus Moxcu, Mal. Blatt., VII, 1860-1, Pp. 205.—SIMPSON, Syn., 1900, p. 607. Unio imbricatus vVoN Martens, Biol. Cent. Am., Moll., 1goo, p. 498, pl. x1111, figs. 6, 6a-c. Umo encarpus Lea, Pr. Ac. N. Sci. Phila., XII, 1868, p. 95; Jl: Ac. N.. Sei. Phila.,. V1, 4868;- p. 2043. plac, tie: S95 Obs., XII, 1869, p. 54, pl. x11, fig. 105. Margaron (Unio) encarpus Lea, Syn., 1870, p. 35. Plagiola encarpa Simpson, Syn., 1900, p. 607. Von Martens has figured in the Biologia Moérch’s Unio mmbricatus and I agree with him that Lea’s Unio encarpus published eight years later is a synonym of the former. There is a good deal of variation in the sculpture, some specimens scarcely showing radial grooves, while in others they are very distinct. The type of Unio encarpus is radially grooved. Group of Plagiola sallei. Shell triangular ovate, inflated, solid, with a high, rounded or narrowly subangulate posterior ridge; beaks full; epider- mis rough and black ; hinge heavy; beak cavities rather deep ; nacre whitish, thicker in front; female shell with a strong marsupial swelling. PLAGIOLA Sus) PLACIOLA SALLEt (Crosse and Fischer). ‘ Shell very solid and inflated, triangular ovate, inequilateral, with a high, narrow, generally slightly biangular dorsal ridge ; beaks full and high, their sculpture not observed ; epidermis rough, blackish, often inclined to crack off; left valve with two pseudocardinals, the hinder triangular, the anterior sub- compressed, and two short, remote, solid laterals, the lower the larger;, right valve with one large, triangular pseudo- cardinal, sometimes with a feeble second one above it, and one lateral; hinge plate rather narrow; beak cavities fairly deep; muscle scars deep; nacre white, much thickened in front. Male shell nearly or quite straight on the base, the posterior biangulation reaching to the hase line; female shell with a decidedly produced marsupial swelling, its slight posterior biangulation elevated to near the middle of the height of the shell. Length (male) 65, height 43, diam. 31 mm. Length (male) 65, height 43, diam. 31. mm. Length (female) 50, height 37, diam. 32 mm. Mexico; Usumacinta and Rio Salinas rivers, Guatemala. Unio sallei Crosse and Fiscuer, J. de Conch., XLI, 1893, p. 179.—Fiscuer and Crosse, Miss. Sci., II, 1894, p- 619, pl. LXVIII, figs. 3, 3a. Var. grossa (von Martens). Shell shorter and higher than the type. very solid, anterior end rounded below, obliquely truncated above; posterior ridge well defined. Length 62, height 44, diam. 30 mm. Guatemala. Unio sallei var. grossus VON MARTENS, 2iol. Cent. Am., Moll., 1900, p: 517, pl. xxxiv, figs. 2, 2a, 2b- There is in the National Museum collection a badly eroded old female shell sent by von Ihering from the Usumacinta River, Guatemala, that I believe belongs to the above species ; probably to von Martens’ variety of it. It is a dead shell, very old and somewhat diseased. The anterior half of the shell 316 PLAGIOLA is greatly thickened, the surface is badly eroded, so that the rough, black epidermis remains only around the later growth, and it has a decided marsupial swelling, thus precluding the possibility that the species can be a Ouaodrula. Group of Plagiola nicaraguensis. Shell much like that of cyrenoides, but simply covered with coarse, irregular, concentric ridges, and having no radiating grooves or wrinkles, faintly rayed in unbonal region. Animal as in the cyrenoides group. PLAGIOLA NICARAGUENSIS (Lea). Shell suboval, rather inflated, subsolid, rounded below and obliquely truncated above in front, with a well-developed, slightly rounded posterior ridge; beaks somewhat full and high, their sculpture consisting of a few fine corrugations, which are somewhat doubly looped; surface strongly concen- trically sulcate, covered with a yellowish-green or olive-green epidermis, which sometimes shows a few faint rays; left valve with two subcompressed pseudocardinals and two laterals, the upper lateral small; right valve with two pseudocardinals, the upper compressed and small, and one lateral, sometimes with a vestige of a second lateral below it; beak cavities moderate, not compressed; anterior scars impressed; posterior scars shallow; nacre bluish-white, sometimes tinted yellowish or flesh-colored in the cavities of the shell. Male shell with rounded base-line, pointed behind at some distance above the base; female shell generally higher than the male, with a wide, rounded marsupial swelling, the blunt posterior point much elevated. Length (male) 46, height 32, diam. 23 mm. Length (female) 40, height 30, diam. 18 mm. Nicaragua. Unio nicaraguensis Lea, Pr. Ac..N. Sci. Phila., XII, 1868, p. 95; JL-Ac. N:-Sei. Phila., VI, 1868,.p. 206, pl: xii, ie, 1077 Obs., XII; 1866, p. 56, pl. xxi, fig. 107. Margaron (Unio) nicaraguensis L&A, Syn., 1870, p. 35. Plagiola nicaraguensis SIMPSON, Syn., 1900, p. 607. TRITOGONIA 217 Unio gabbianus Lea, Pr. Ac. N. Sci. Phila., XII, 1868, p. 95; jee. Ns oer Philas Vi, 1866; p: 205, pl. xxi, fig. 106; Obs XU! 1860; ps. 55, ‘pl: xii, ‘fig: 106. Margaron (Unio) gabbianus Lia, Syn., 1870, p. 35. Lea’s type is a female shell, and the type of his Unio gabbi- anus is a male shell, which [ believe belongs to the same species. I have examined a large amount of material belong- ing to this group and of this species and it seems to vary much in the degree of inflation and the length of its shell. DIGEN. Male shell inflated, truncated posteriorly ; female shell com- pressed, expanded into a broad wing behind the post-ridge, the wing being filled with a flap of the mantle. Genus TRITOGONIA Agassiz, 1852. Tritogonia Acassiz, Arch. fur Nat., 1852, p. 48. Shell solid, elongate rhomboid, having -a strong, irregular posterior ridge ; obliquely truncated behind in the male; in the female this region is somewhat truncated and rounded; base incurved; whole surface, except the rounded wing of the females, covered with pustules; beaks rather low, incurved and turned forward over the well-developed lunule, which is elongated and filled with epidermal matter; beak sculpture strong, consisting of irregular, subparallel ridges, which are curved upward behind, and fine radiating ridges in front of and behind this; epidermis dark olive; hinge plate rather nar- row; pseudocardinals strong, ragged; laterals long and straight, near to the pseudocardinals. Animal having the inner gills much larger than the outer, generally. free for the most part from the abdominal sac ; palpt enormous, elongated, united to each other behind and to the mantle a part of their length; mantle thin, with a thickened, dark, double border, the inner edge often toothed throughout, the base much thickened at the posterior end and folded at the branchial opening: branchial opening large, with numerous 318 TRITOGONTA crowded papillz ; anal opening smooth or with only fine dentic- ulations; superanal opening long, closed below; in the female there is a thickened flap of the mantle, which fills the circular posterior expansion of the shell, and which has a smaller flap inside; foot and abdominal sac large, the latter winged in front. Marsupiam occupying all four gills. Type, Unio verrucosus Say. The genus Tritogonia is one of the most remarkable in the Unionide. In all other genera and groups where the shells are sensibly dimorphous the female shell is swollen and ex- tended at the posterior base in front of the posterior ridge, while the male shell is without this swelling. But in Tyrito- gonia none of the shells are produced at the posterior base, but that of the female is produced behind the posterior ridge, spreading out in a thin, wide, rounded wing or flap at the extreme hinder end of the shell, while that of the male is obliquely truncated below and ends behind in a more or less decided point. In the other dimorphic groups the female shell has, as a rule, a greater diameter than the male, and is never more compressed. But in this peculiar form the male shell is much more inflated generally than that of the female. TRITOGONIA TUBERCULATA (Barnes). Shell large, elongated, solid, subrhomboid, scarcely inflated, inequilateral, with a decided, curved, elevated ridge, which ends well forward on the posterior base, in front of which for a long distance there is a shallow excavation; beaks low, compressed, sculptured with strong, irregular, corrugated ridges that turn up behind: surface covered as far back as the posterior ridge with irregular, different sized pustules, which sometimes form somewhat chevon-shaped figures; behind the ridge the sculpture consists of strong, irregular, curved, cor- rugated and often knobbed ridges; epidermis greenish-brown, or brown, dark green in young shells; left valve with two ragged, triangular pseudocardinals and two straight laterals; right valve with one large pseudocardinal, a small one in front of it, and vestigial teeth behind it, with one lateral, which in TRITOGONIA 219 heavy shells may be partly double; beak cavities moderately deep, compressed; anterior scars rough; posterior scars oval ; nacre white, rarely purple. In this remarkable species the male shell 1s obliquely truncate at the posterior base, behind the posterior ridge and ends in a somewhat blunt point consider- ably above the base line. From this point running towards the beaks there is generally a row of low, broad nodules or knobs that extend upward in ridges. In the female shell this area is much smoother, and is extended into a broad, rounded wing. Length (male) 125, height 80, diam. 40 mm. Length (male) 150, height 88, diam. 50 mm. Length( female) 125, height 70, diam. 35 mm. Length (female) 190, height 103, diam. 48 mm. Mississippi drainage generally; streams falling into the Gulf of Mexico from the Alabama system west to central exas. Type locality, Wisconsin. Unio tuberculatus Barnes, Am. Jl. Sci., VI, 1823, p. 125, pl. vu, figs. 8a, 8b.—RkEEveE, Conch. Syst., I, 1841, p. 118, pl. LXXXVII, fig. 5—Hantey, Biv. Shells, 1843, p. 182, pl. xx, fig. 27.—Porigz and Micuaup, Gall. Moll., 1844, p. 158, pl. LX, fig. 1—RrxEvE, Elements of Conch., 1860, II, pl. xxxm1, fig. 183. Margarita (Unio) tuberculatus Lea, Syn., 1836, p. 17; 1838, po 1G; Margaron (Umo) tuberculatus Lia, 1852, p. 23; 1870, p. 34. Mya tuberculata Eaton, Zool. Text-Book, 1826, p. 217. Tritogomia tuberculata SIMPSON, Syn., 1900, p. 608. Quadrula tuberculata ORTMANN, Ann. Car. Mus., VIII, 1912, P. 254. Umio pustulata Swainson, Treat. on Mal., 1840, p. 271, fig. 54d. Umo gigas Sowrersy, Conch. Icon., XVI, 1867, pl. Lv1, fig. 287. Unio verrucosus Say, Am. Conch., VI, 1834.—Kuster, Conch. Cab., 1862, p. 273, pl. xc, fig. 1—Sowrrry, Conch. Icon., XVI, 1868, pl. 1, fig. 4. 320 TRITOGONIA Tritogonia verrucosa AGaAssiz, Arch. fur Nat., I, 1852, p. 48. Tritigonia verrucosa Smiru, Bull. U. S. Fish Com., 1899, p. 201, pl. GARR. Quadrula tritogonia ORTMANN, Naut., XXII, 1909, p. 101. Quadrula obesa VANATTA, Naut., XXIII, 1910, p. 102. Quadrula parkeri Griser, The Academician, I, 1911, p. 15. I have never seen a specimen among the hundreds examined that had young or ova in the gills. But I have seen sperma- tozoa in specimens with inflated shells and ova in those with the wing. Mr. H. M. Kelly, of Mount Vernon, lowa, who has made a very careful study of the anatomy of many of our Unionidze, assures me that the form with the compressed shell, having the expanded flap behind, is the female. It has been claimed that this species was previously de- scribed under the name of Obliquaria verrucosa by Rafinesque, but I am unable to make anything out of his figure or description; hence I use the name given by Barnes. Barnes’ name was used by Rafinesque for the species which the former called Unio verrucosus, but as Rafinesque placed his species in Obliquaria, and as the generic names of both forms are changed in this work, I do not consider Barnes’ name preoc- cupied. Female shells seem to generally grow larger than those of the males. Var. obesa Simpson. Shell much smaller than the type and very much more inflated, the sculpture finer and arranged in broken ridges or nodules so as to form more or less perfect chevron-shaped patterns ; posterior flap of the female less developed than in the type. Length (male) 78, height 47, diam. 33 mm. Length (female) 75, height 50, diam. 30 mm. Texas; Louisiana; Mississipp1. Type locality, Big Eddy, Nechez River, Texas. Tritogonia tuberculata var. obesa SIMPSON, Syn., 1900, P. 609. This variety is distinct enough to almost have specific rank, but as I have seen only a limited amount of material and as TRITOGONIA aaa the species is quite variable, I place it here as a variety. Occa- sional specimens found as far north as southern Ohio seem to stand somewhat between the two forms. TRITOGONIA NOBILIS (Conrad). Shell solid, inflated, inequilateral; beaks full and high, turned forward over a strong lunule that passes underneath them, their sculpture consisting apparently of doubly-looped, zigzag bars; anterior end rounded, sometimes slopingly trun- cate or angled above; base incurved in front of the pos- terior ridge; posterior ridge double, with a radial depression in front of it, and sometimes one above it; surface generally having strong, irregular growth lines and more or less covered with tubercles. There is usually a row of rounded tubercles running down the front angle of the posterior ridge and an irregular, sometimes double, radial row of elongated knobs in front of the middle of the shell and these are stronger than the pustules on the rest of the shell; dorsal slope having curved nodulous or subnodulous ridges; epidermis brown; pseudo- cardinals double, strong and ragged in the left valve, single in the right, often a good deal split up; laterals straight, dou- ble in the left valve, single or occasionally semi-double in the right; beak cavities rather deep; dorsal scats in a row under the beaks: anterior scars impressed, rough; posterior scars shallow; nacre white or dull purple, iridescent behind. Male shell subquadrate ; female shell drawn out behind at the biang- ulate termination of the posterior ridge so that it is often wedge-shaped when viewed from above, less inflated in pro- portion to length than the male shell. Length (male) 80, height 69, diam. 47 mm. Length (female) 110, height 76, diam. 47 mm. Length (female) 114, height 77, diam. 50 mm. Red River of the North to Mississippi; Louisiana (the type coming from Bayou Teche) ; west into eastern Texas. Unio nobilis Conran, (part), Jl. Acad. N. Sci. Phila., IT, 1854, Pp. 2907,-pl. Rxvar wie. 3. Quadrula asper, (part), Stmpson, Syn., 1900, p. 776. 322 TRITOGONTA Unio lunulatus Pratt, Pr. Dav. Acad. N..Sci., I, 1876, p. e ehO7, ph Rae; fig, Te Ouadrula lachrymosa var. lunulata Stimpson, Syn., 1900, p. 777: Conrad’s description of Unio nobilis is not very explicit and he figures two specimens. His figure No. 2 is the same as Say’s apiculatus, | am sure. Figure 3 represents a large shell 114 millimeters in length, considerably drawn out and rounded behind at the termination of the double posterior ridge. I had never seen anything like it at the time I wrote the Synopsis and thought it might be an abnormal specimen. Recently Mr. J,orraine S. Frierson has sent me two shells, one of which, from Grand River, Missouri, is almost exactly like Conrad’s figure 3, being drawn out behind and decidedly wedge-shaped when viewed from above. The other is a much shorter shell, more inflated in proportion to its length and is almost squarely truncated behind, in fact the upper part of the truncation overhangs a little. Some specimens are tubercu- late throughout; others show little more than the two rows of strong knobs, and a valve from the Red River of the North is slightly compressed and almost destitute of nodules. I ami inclined to believe that Pratt’s Unio lunulatus from near Rock Island, Illinois, is a smooth inflated form of Conrad’s nobilis, a male shell probably. [ cannot be sure as to the relationships of this species, but am inclined to place it with Tritogonia. ‘The female of Lea's Unio lachrymosus has all four of the gills filled with embryos forming smooth pads, and the shells, so far as I have seen, are not dimorphic. I have never seen a gravid Unio tubercu- latus of Barnes, but specimens recently examined in which the shell was drawn out into a rounded wing behind appeared to have the outer gills recently filled, as the apparent ovisacs were still distended and seemed to be separated by sulci. The inner gills gave no indication of having been filled with young. TRITOGONIA CONJUGANS (B. H. Wright). ‘Shell long rhomboid, solid, inflated, inequilateral; beaks probably low and compressed; posterior ridge high, and in HEMILASTENA 323 front there is a-wide, shallow, radial depression ; posterior end truncated; surface covered with strong, irregular tubercles, those on the posterior slope partially arranged in curved rows; just at and back of the posterior ridge there are faint indica- tions of knobs; epidermis brown; left valve with two strong pseudocardinals, the posterior one bifid and two strong lat- erals; right valve with three pseudocardinals, the middle one much the largest, and one double lateral; anterior scars rough; posterior scars oblong; beak cavities moderately deep, com- pressed; pallial line deep and roughened; nacre lurid white, much thicker in front, with two faint, wide, radial depressions, one at the post-ridge, the other in front of the middle. Length 03.75, height 68.75, diam. 50 mm. Type localitv, Hiawassee River, Tennessee. Unio conjugans B. H. Wricu’t, Naut., XIII, 1899, p. 80. Tritogonia conjugans Simpson, Pr. Ac. N. Sci. Phila., 1900, p- 79, pl. iv, fig. 1—Syn., 1900, p. 609. I am not at all certain as to the systematic position of this species. The posterior truncation is much different from that of T. tuberculata, but the epidermis and tubercles, the hinge, beak cavities and pallial line are very much as in that species. A single male shell of this remarkable species, the type, is in the U. S. National Museum collection. Genus HEMILASTENA (Agassiz, 1852) Simpson. Hemilastena AcaAssiz, Arch. fur. Nat., I, 1852, p. 50.—Simp- SON, Syn., 1900, p. 673. Shell small, elongate elliptical, rounded in front and behind, often slightly incurved at the central base; beaks rather sharp, but not full; sculpture consisting of fine, parallel ridges, which are looped up in the middle and open behind ; epidermis brown- ish, rayless; teeth imperfect, a single irregular, compressed tooth in each valve; that of the left under the beak, that of the right in front of it; laterals nearly or quite wanting; anterior end of the shell much thickened ; anterior muscle scars united ; posterior faint; nacre dull whitish. 324 HEMILASTENA Marsupium filling the entire outer gills and forming enor- mously thickened pads, the upper part finely vertically striate, the lower part of different texture, lighter colored, wrinkled and granular on the surface: embryos very large; outer and inner gills nearly alike in size, the latter free from the abdomi- nal sac, all united to the mantle to their posterior ends; palpi elongated, granular; mantle straight below, thickened on the border ; branchial opening large, with numerous light-colored papilla with dark lines; anal opening black, without papille, separated from the small superanal opening by a long bridge; hinder part of the mantle, branchial and anal openings widely separated by the very thick marsupia. Type, 4Alasmodonta ambigua Say. From the examination of a large series of fine specimens sent by Mr. L,. E. Daniels, I can only conclude that this curious form is quite different from any other [ know. The marsu- pium is decidedly vertically striate throughout its upper half, the lower half is lighter, granular and wrinkled externally and in places shows traces of vertical sulci as in the higher Uniones, Lampsilis, etc. The males seem to be much less numerous than the females, only two being found in the lot sent by Mr. Daniels. Their shells are less inflated, more nearly straight below and not so broad posteriorly; those of the fe- males being decidedly swollen behind, the posterior ridge being very full and widely rounded, the base line sometimes a little incurved in the middle and the hinder end of the shell broad. The shells of this little species bear a strong superficial resemblance to those’of the genus Margaritana. They differ, however, in several minor characters and one of the most important is in the beak sculpture. That of Yemilastena has fine ridges, which are looped up in the middle and pass down- ward and backward obliquely and are open behind, while the sculpture of Margaritana consists of strong, straight folds. In the latter genus the mantle is more or less attached to the cavities of the shell by small muscles, which leave scars when the animal is taken out, a character not found in Hemilastena. HEMILASTENA 325 All four of the gills are united to the mantle behind to their extreme ends, while in all species of Margaritana they are free behind. HMILASTENA AMBIGUA (Say). Shell small, oblong, with dorsal. and basal lines parallel, the anterior and posterior ends rounded, inequilateral, sub- solid, not inflated; beaks not full or elevated, their sculpture consisting of fine ridges looped up in the middle and open behind ; posterior ridge wide and rounded, often raised above the disk; surface with delicately sulcate growth lines; epider- mis greenish or olive-brown; there is a single low, smooth tooth in each valve at the beaks; nacre thin behind, where it is subtranslucent and tinted with dirty purplish; at the anterior base it is thickened and creamy white. Length 40, height 19, diam. 12 mm. Length 48, height 21, diam. 16 mm. Ohio River system; north to Michigan ; west to Iowa; south to Arkansas; east to Tennessee. Type locality, Northwestern Territory. Alasmodonta ambigua Say, Jl. Ac. N. Sci. Philas..V, 1825, PisT: Margaritana ambigua Kuster, Conch. Cab. Unio, 1862, p. 300, pl. xcix, fig. 7. Hemilastena ambigua Simpson, Syn., 1900, p. 673. Unio hildrethianus Lea, Tr. Am. Phil. Soc., V, 1834, p. 36, pl. m1, fig. 8; Obs., I, 1834, p. 148, pl. 11, fig. 8 Haney, Biv. Shells, 1843, p. 196, pl. xxuu, fig. 38.—Kuster, Conch. Cab. Unio, 1861, p. 206, pl. 1xvin, fig. 8—Sowersy, Conch. Icon., XVI, 1866, pl. xxxvi, fig, 192—Baxer, Moll. Chi- cago, Pt, 1868, p..7 1), pl: v, die. i Margarita (Unio) hildrethianus Lea, Syn., 1836, p. 28: 1838, pe -20; Margaron (Margaritana) hilarethianus Lia, SVU; [652° p. 43; 1870, p. 60. Strophitus hildrethiana Conrap, Pr. Ac. N. Sci. Phila., VI, £8535, p. 203. 326 CYPROGENIA Baphia luldrethiana H. and A. Avams, Gen. Rec. Moll., II, 1857, Pp. 499. Margaritana hildrethiana B. H. Wricutr, Check List, 1888. sometimes constricted at the center of the base; beaks rather full with a few coarse, subparallel, concentric ridges, which are curved up rather suddenly behind, and back of these there are fine radiating ridges ; epidermis smooth, shining, often ray- ed: hinge line slightly incurved in front of the beaks, edentu- lous or bearing the merest rudiments of teeth: muscle scars: shallow, irregular; nacre bluish-white. ANODONTOIDES 467 Animal with marsupium occupying the outer and sometimes the four leaves of the branchiz ; ovules more numerous in the outer, the whole pad-like; gills large, inner semicircular, inee from the abdominal sac, or united to it; branchial- opening large, with many small papille ; anal opening with well-devel- oped papillre. ‘Type, Anodonta ferussaciana Lea. ANODONTOIDES FERUSSACIANUS (Lea). Shell long elliptical, scarcely subsolid, inequilateral, subin- flated; beaks full and high, sculptured with a few concentric ridges, which curve upward behind and are suddenly and an- gularly turned upward and forward, returning as fine raised threads to the nucleus and behind the other sculpture there are several radiating, raised lirze. Posterior ridge rounded or some- times faintly biangulate, ending behind about on the median line: anterior end rounded; posterior end rounded, feebly pointed or biangulate ; dorsal line slightly incurved in front of the beaks: basal line nearly straight, often faintly incurved in the middle; epidermis greenish, often faintly rayed ; hinge line often a little swollen in front of the beaks where it is incurved, otherwise usually edentulous; nacre bluish-white or bluish, generally bright and iridescent. behind. Length 86, height 45, diam. 34 mm. Length 92, height 53, diam. 40 mm. Mississippi drainage area generally; St. Lawrence River system; Red River of the North; Saskatchewan River ; Connec- ticut ? Type locality, Ohio River, Cincinnati, O. Anodonta ferussaciana Lea, Tr. Am. Phil. Soc., V, 1834, P- 4s, pl. vi, fig. 15; Obs., I, 1834, p. 157, pl. v1, p. 15.—Mus- crovE, Phot. Conch., 1863, pl. 1, fig. 15.—Cressin, Conch. Cab» Ano,, 1873, pi 75; pl. xxut fig. Anodon ferussaciana Dr. Kay, Zool. of N. Web oc TOA, 1p. 200, pl. xvi, fig. 230.—SOWERBY, Conch. Icon., XVII, 1867, pl. x1v, fig. 51. 468 ANODON TOIDES Margarita (Ancdonta) ferussaciana Lea, Syn., 1836, p. 51; 1838, p. 30. Margaron (Anodonta) ferussaciana Lea, Syn., 1852, p. 50; 1870, p. 79. Anodontoides ferussacianus BAKER, Moll. Chicago, Pt. 1, 1898, p. 72, pl. m1, fig. 6; v, fig. 2-—SIMPSON, Syn., 1900, p. 659. Anodonta argentea Lea, Pr. Am. Phil. Soc., I, 1840, p. 289; Tr. Am. Phil. Soc., VII; 1842, p..223, pl. xix; fig..41 ; Obse III, 1842, p. 61, pl. xix’ fig. 41.—C1essin, Conch. Cab. Ano., 1876, p. 2r0, pl. LXXN, OPS. 3; 4. Margaron (Anodonta) argentea Lea, Syn., 1852, p. 50; 1870, Dp. 79: Strophitus argenteus Conrap, Pr. Ac. Nat. Sci. Phila., VI, 1853, p. 262. Anodonta ferruginea Lea, Pr. Am. Phil. Soc., I, 1840, p. 289; Tr. Am. Phil, See; Vill, 1842, ip. 225. pl six, ee Obs., III, 1842, p. 63, pl. xrx, fig. 43.—Muscrove, Phot. Conch., 1863, pl. 1, fig. 2—CzEssin, Conch. Cab. Ano., 1876, p. 20, pls taeKn, Bes: 50. Margaron (clnodonta) ferruginea Lwa, Syn., 1852, p. 50; 1870, Ds:79: Anodon plicatus HAatpEMAN, Jl. Ac. Nat. Sei. Phila. VIII, 1842, p. 201. Margaren (Anodonta) plicata Lea, Syn., 1870, p. 79. Anodonta denigrata Lea, Tr. Am, Phil. Soc., X, 1852, p. 285, pl. xxv, fig. 45; Obs., V, 1852, p. 41, pl. xxv, fig. 45—CrEs- sin, Conch. Cab. Ano., 1875, p. 210, pl. LXIVv, figs. 4, 5. Margaron (Anodonta) denigrata L&A, Syn., 1852, p. 50; 1870, Pp. 79- Anodonta oblita Lea, Tr. Am. Phil. Soc., X, 1852, p. 290, pl. Xxviu, fig. 52; Obs., V, 1852, p. 46, pl. xxvii, fig. 52.— Cresstn, Conch. Cab. Ano., 1875, p. 165, pl. Liv, figs. 7, 8. . Margaron (Anodonta) oblita Les, Syn., 1852, p. 50; 1870, p. 79: Anodon subcylindracea Sowerny, Conch. Icon., XVII, 1867, pl. xrv, fig. 47. ANODON TOIDES 469 Anodonta subcylindracea Curssin, Conch. Cab. Ano., 1873. p: g2 pl. xxvii figs. 6, 7. Many specimens resemble certain forms of Strophitus eden- tulus so closely as to even deceive experts. Generally the shell is thinner than in that species, though I have before me an A. ferussacianus belonging to the Lea collection from Cincin- nati, Ohio, which is as solid as any Strophitus | have ever seen. Usually the hinge of 4. ferussacianus does not show quite as much of a development of teeth as does the S. edentulis, the shell is more nearly elliptical, is more evenly rounded behind, is straighter on the basal line and smoother than edentulus. Finally the beak sculpture is not so strong and wide as it is in the latter species. The character of the marsupia is very dif- ferent in the two genera. Var. buchanensis (Lea). Shell smaller, more elongated and delicate than the type, more disposed to be biangulate and widened behind. Length 76, height 36, diam. 27 mm. St. Lawrence System. Type locality, Buck Creek, O. Anodonta buchanensis Lua, Tr. Am. Phil. Soc., VI, 1838, p. 47, pl. xiv, fig. 43; Obs., II, 1838, p. 47, pl. x1Vv, fig. 43.— Sowrrpy, Conch. Icon., XVII, 1869, pl. xx1v, fig. 92. Margarita (Anodonta) buchanensis Lea, Syn., reaon 2p. 543 1838; p- 32. Margaron (Anodonta) buchanensis L&E, Syite 1652). p: 1870, p. 82. Anodonta subcylindracea Lea, Tr. Am. Phil. Soc., Vi, 1838, Dp. 106; pl. xxiv, fig. 117; Obs., Il, 1838, p. 106, pl. xxiv, fig. 117.—Wat ton, Moll. Monroe Co., 1892, p. 17, pl. vil, fig. 3. Margarita (Anodonta) subcylindracea Ima, Syn., 1838, p. 32. Anodon subcylindracea Dr Kay, Zool. BintiteN “ts 5, -1643, p. 200, pl. xvz, fig. 220. Margaron (Anodonta) subcylindracea Lea, Syn., 1852, p- 51; 1870, p. 82. 470 ANODON TOIDES Anodontoides subcylindraceus BAKER, Moll. Chicago, Pt. 1, 1808, p. 74, pl. iv, fig. 4; v1, fig. I. Anodontoides ferussacianus var. subcylindraceus SIMPSON, Syn., 1900, p. 660. I am doubtful whether the type of Anodonta buchanensts is in Lea’s collection. There is a shell placed with a number of others (Museum number 86719) labeled “Anodonta buchan- ensis, Buck Creek, M. G. W.,” which in size and general form is much like his figure of that species, but the outlines do not closely agree. The shells placed under this number vary be- tween this and typical ferussacianus. It probably equals Lea’s A. subcylindracea, the type of which I have not seen. ANODON'TOIDES MODESTUS (Lea). Shell small, long obovate or subrhomboid, being a little wider behind than in front, thin or almost subsolid, inequilateral, subinflated ; beaks moderately full and elevated, rather sharp, sculptured with a number of parallel, somewhat doubly-looped ridges, which turn up behind and return to the nucleus in the form of delicate raised threads ; behind these there are a num- ber of radial threads; posterior ridge subbiangular, almost double, ending behind below the median line in a feeble bian- ulation ; base full just behind the middle, in front of it straight or a very little emarginate; surface with uneven growth lines ; epidermis ashy-green with darker bands with two or three dark rays on the posterior slope; hinge line a very little in- curved in front of the beaks where it is scarcely thickened ; nacre bluish, subshining, iridescent behind. Length 47, height 24, diam. 17 mm. Type locality, Pond near Kalamazoo, Michigan. Anodonta modesta Les, Pr. Ac. Nat. Sei. Phila., 1857, p. 84; Jl. Ac. Nat Sci, Phila‘; LV, 1860; p:.364) plexi, fexaso; Obs., VIII, 1860, p. 46, pl. x1, fig. 189.—Cresstn, Conch. Cab. Anos.1874,.p.°153, ph aise fiess 7, ie. Margaron (Anodonta) modesta LEA, Syn., 1870, p. 79. ‘Inodon modestus SowreRsBy, Conch. Icon., XVII, 1867, pl. x, fig. 26. ANODONTOIDES 471 Anodontoides ferussacianus var. modestus SIMPSON, Syn., 1900, p. 660. The type, which is in the Lea collection, is the only specimen I have seen, which I feel certain is the true 4. modesta of Lea. It is nearly subsolid, is elongated, full at the base just behind the middle and slightly biangulate behind. The hinge is al- most exactly like that of what is commonly called Ano- donta subcylindracea, but the beak sculpture differs consider- ably, being finer and doubly looped. There are a number of other shells in the general collection of the National Museum, labeled Anodonta modesta, some of them by Dr. Lewis, which may be a variety of 4. pepiniana, others are perhaps a form of the variety buchanensis. I am a little at a loss where to place the present form, which has all the characters of an Anodontoides except the bealx sculpture. ANODONTOIDES ELLIOTTIL (Lea). Shell somewhat elongated, subelliptical, rather inflated and thin, with a moderate subangular posterior ridge, inequilateral, the beaks rather full but not very high, their sculpture a few moderate ridges that curve up sharply behind; epidermis brownish or brownish-green, generally faintly rayed with light- er colored, narrow rays; hinge line slightly incurved in front of the beaks, with a rudimentary, compressed anterior tooth in each valve; without laterals; beak cavities not deep; muscle scars superficial ; nacre bluish. Length 73, height 38, diam. 28 mm. Type locality, Chattahoochee River, Columbus, Georgia. Also Columbus, Mississipp1. Margariiana elliott: Lea, Pr. Ac. N. Sci. Phila., II, 1858, p. 16a jieAc, Nese, Pilg PV 1e50; p, 226, pl. Xxxi, fig. 108 ; Obs. V LE1850,.p:/44, pl. xxxi, fies 108. Margaron (Margaritana) elliottti L&a, Syn., 1870, p. 68. Margaritana (Alasmodonta) elliottii Cresstn, Conch. Cab. ANG, W876, p.1267,.pl: LXeXIT, figs. 3,4. Strophitus elliottii Simpson, Syn., 1900, p. 619. 472 PEGIAS Margaritana elliptica Lex, Pr. Ac. N. Sci. Phila., II], 1859, p- 113; Jl. Ac. N. Sei. Phila., V, 1862, p. 106, pl. xviit, fig. 254 ;. Obs., VIII, 1862, p. 110, pl. xvim1, fig. 254. Margaron (Margaritana) elliptica Lea, Syn., 1870, p. 68. Margaritana (Alasmodonta) elliptica Ciesstx, Conch. Cab- Ano., 1876, p. 270, pl. LxxxI, figs. 5, 6. Anodonta showalterti Lea, Pr. Ac. N. Sci. Phila., [1V, 1860, p- 307; JI. Ac. N. Sci. Phila., 1862, p. 215, pl. xxxim, fig. 284; Obs., IX, 1863, p. 37, pl. «xxi, fig. 284.—-CLessin, Conch. Cab. Ano., 1874, p. 156, pl. 11, figs. 5, 6. Anodon showalterti Sowersy, Conch. Icon., XVII, 1870, pl. XXvII, fig. 104. Margaron (Anodonta) showalteru Lea, Syn., 1870, p. 79. Strophitus edentulus (part), SIMPSON, Syn., 1900, p. 617. I placed this species in Strophitus with some doubt when 1 wrote the Synopsis. Since writing that I have seen other specimens, which show something of the beak sculpture, and I am rather inclined to believe that it is closely allied to A. ferussacianus. The teeth are better developed than in that species, but the nearly straight hinge line and the beak sculp- ture would seem to indicate that it is an Anodontoides. On comparing again Lea’s Anodonta showalteru with his Mar- garitana elliottii I am satisfied that the two are identical, the former being merely a little more solid and having a slightly heavier hinge. I had overlooked the fact that Lea in describ- ing the soft parts of the former states that the “Branchial uterus is filled with embryonic shells the whole length of the outer leaves” as in Anodonta ferussaciana and not as in A. edentula. The beak sculpture of this form is rather delicate. Genus PEGIAS Simpson, 1900. Pegias SIMPSON, Syn., 1900, p. 660. Shell small, thickened in front, with a sharp posterior ridge, in front of which is a wide radial depression, ending in a basal sinus; above this ridge is another, making the shell decidedly biangulate and truncate behind; beak sculpture consisting of PEGIAS 473 subconcentric corrugations, generally swollen on the posterior ridge; epidermis decorticated, but showing a few dark, radial rays on the base of the shell ; pseudocardinals rather solid ; lat- erals wanting. Animal having the marsupium empty in the specimen examined; inner gills larger in front, free from the abdominal sac, all four truncated behind; palpi large; mantle with square spots on its edge; branchial opening with a few large papilla: anal opening smooth, not separated from the superanal. Type, Margaritana fabula Lea. PEGIAS FABULA (Lea). Shell oblong, subcompressed, solid, inequilateral; beaks not very full or high but pointed, sculptured with four or five very strong folds, which run parallel with the growth lines or are slightly oblique; posterior ridge angular, ending behind in an angulation at the base of the shell; there is another ridge on the posterior slope near the dorsal line, which also ends behind in an angulation; posterior end truncated between these ridges either squarely or obliquely ; often the upper point extends be- yond the lower one; base line generally incurved in front of the posterior ridge; epidermis decorticated, rayed below and be- hind, often widely below; left valve with an irregular triangu- lar tooth under the beak, sometimes with a vestige of another in front of it; right valve with one tooth in front of the beak ; laterals wanting or represented by mere blurred, faint ridges; beak cavities rather deep, compressed; anterior muscle scars impressed ; nacre whitish on the anterior border, flesh-colored or salmon in the cavities, greatly and suddenly thickened in front. Length 35, height 22, diam. 12 mm. Length 30, height 16, diam. 11 mm. Cumberland and Tennessee River systems. Type locality, Cumberland River, Tenn. Margarita (Margaritana) fabula Lea, Syn., 1836, p. 46; 1838, p. 28. 474 PEGIAS Margaritana fabula Lea, Tr. Am. Phil. Soc., VI, 1838, p. 44, pl. x1u, fig. 39; Obs., II, 1838, p. 44, pl. xii, fig. 39.—Kus- TER, Conch. Cab. Unio, 1862, p. 301, pl. c, fig. 3. Unio fabula Han Ey, Biv. Shells, 1843, p. 213, pl. xx, fig. 45. —Sowersy, Conch. Icon., XVI, 1868, pl. Lxxvy, fig. 394. Margaron (Margaritana) fabula Lea, Syn., 1852, p. 44; 1870, p. 70. Micromya fabula Acassiz, Arch. ftir Nat., I, 1852, p. 47. Strophitus fabula Conrap, Br. Ac. Nat. Sci. Phila., VI, 1853. p. 263. Baphia fabula H. and A. Apams, Gen. Rec. Moll., II, 1857, p. © 499. Pegias fabula SIMPSON, Syn., 1900, p. 661. Margaritana curreyana Lea, Pr. Ac. Nat. Sei. Phila., I, 1840, p. 288; Tr. Am. Phil. Soc., VIII, 1842, p. 223, pl. xviut, fig. 40; Obs., III, 1842, p. 61, pl. xvii, fig. 40.—Kuster, Conch. Cab. Unio, 1862, p. 300, pl. c, fig. 2. Micromya curreyana Acassiz, Arch. fur Nat. I, 1852, p. 47. Margaron (Margaritana) curreyana La, Syn., 1852, p. 42; 1870, p. 68. Strophitus curreyana Conran, Pr. Ac. N. Sci., Phila., VI, 1853, Pp. 262. Baphia curreyana H. and A. Apams, Gen. Rec. Moll., II, 1857, p- 400. Unio curreyana SOWERBY, Conch. Icon., XVI, 1868, pl. LXx1t1, fig. 3109. ° Unio currevanus Haney, Biv. Shells, 1856, p. 386, pl. xxiv, fig. 10, Margaritana correyana PaireL, Conch. Sam., III, 1890, p. 173. A remarkable form, which seems to be related to some of the Alasmidontas, but differs from all of them in a number of characters. Its texture and epidermis are unlike any species that I know of. Usually much of the epidermis is decorticated, even in young shells, leaving a grayish or ashy surface exposed. It often remains in the sinus near the base in front of the posterior ridge, where it shows a very wide dark ray or blotch, and when present on the posterior end it quite commonly shows ARCIDENS A75 rays. The beak sculpture is remarkably strong, oiten extend- ing well on to the body of the shell in oblique ridges. The posterior truncation between the two ridges may be square Or the upper point may project far beyond the lower one. The teeth are much as in Alasmodonta, but the texture and decided thickening of the nacre in front as well as the decided trun- cation of all four of the gills behind are peculiar. Genus ARCIDENS Simpson, 1900. Arcidens SIMPSON, Syn., 1900, P- 661.—OrtMANN, Ann. Car. Mus., VIII, 1912, p. 284. { Shell subsolid, inflated, subrhomboid, with full, high beaks ; beak sculpture very strong, consisting of irregular corruga- tions, which fall into two loops, at the bases of which the ridges are swollen into knobs that continue out in two radiating rows on to the disk of the shell; in front of and behind the beaks are many fine, radial wrinkles, the posterior ones being zig- zagged; surface of the shell covered with oblique folds and wrinkles; epidermis dark olive, shining ; there are two elon- gated, compressed pseudocardinals in the left valve, the pos- terior under the beak, and curved upward, cutting off the hinge plate in the right valve, which has a single, compressed pseu- docardinal in front; laterals numerous, short, blurred ; muscle scars irregular ; nacre white. Animal with the gills very large, rounded below ; inner the larger, free from the abdominal sac ; marsupium filling the outer gills, of a peculiar, granular tex- ture; palpi very large, elongated, attached half way to the mantle: mantle with a thick, unspotted border ; branchial open- ing large, papillose ; anal opening with rudimentary papille. Type, Alasmodonta confragosa Say. ARCIDENS CONFRAGOSUS (Say). Shell rhomboid, inflated, subsolid, or solid, slightly inequi- lateral; beaks high and full, their sculpttire consisting of irreg- ular, doubly-looped ridges, the bases of the loops being devel- oped into strong, pinched-up nodules, which extend out on to the disk of the shell; in front of and behind the loops there are 476 ARCIDENS a number of radiating, wavy, subnodulous lire or small ridges ; from the anterior row of knobs extending backwards and downwards there is a series of strong folds and these are crossed by wrinkled, radiating, sometimes zigzagged, threads ; the posterior slope has radial, wrinkled sculpture, while the an- terior base has usually merely concentric striz ; posterior ridge rather high; post-dorsal region almost winged; epidermis brownish-green with dark bands, sometimes clouded ; left valve with an arched, somewhat elongated tooth under the beak, which often curves upward; in front of this there is a com- pressed tooth; right valve with a strong, subcompressed tooth in front of the beak; at the beak the hinge plate is cut away for the reception of the tooth in the left valve; laterals reduced to blurred, uneven vestiges; beak cavities deep; muscle scars. shallow; nacre bluish-white, dull, often with uneven radial sculpture, with a wide prismatic border. Length 100, height 75, diam. 48 mm. Mississippi River and states adjoining it; Ohio River drain- age; southwest to Colorado River, Texas; Bayou Teche, Lou- isiana; ? Enterprise, southeastern Alabama. Type locality, New Orleans, La. Alasmodonta confragosa Say, N. Harm. Diss , II, 1829, p. 339; Am. Conch., I, 1830, pl. xx1—CHENUu, Bib. Conch., Ist ser., III, 1845, p. 30, pl. vim, figs. 1, Ia. Margarita (Margaritana) confragosa Lea, Syn., 1836, p. 433 1838, p. 27. Unio confragosa DrsHayes, An. sans Vert., 2d ed., VI, 1 p. 552.—HAn ey, Biv. Shells, 1843, p. 210, pl. xx1, fig —DesHayes, Tr. Elem., 1853, p. 217, pl. xxx, figs. 5-7. Baphia confragosa H. and A. Apams, Gen. Rec. Moll., II, 1857, p. 500. Margaron (Margaritana) confragosa Lua, Syn., 1852, p. 42; 1870, p. 67. Margaritana confragosa CaLKtns, Pr. Ottawa Acad., 1874, p. 46. Unio confragosus Sowrrsy, Conch. Icon., XVI, 1867, pl. Lx, fig. 299. 835, a ARKANSIA 477 Arcidens confragosus SIMPSON, Syn., 1900, p. 661.—ORTMANN, Ann Car. Mus., VIII, 1912, p. 284, figs. 12-12a. A remarkable form, which does not seem to be very closely related to any other known species, except the recently de- scribed Arkansia wheeleri. ‘The sculpture is exceedingly com- plicated, that of the beaks with the two rows of nodules being something as it is in Quadrula lachrymosa. The oblique wavy folds recall those of the plicata group of Quadrula, but the teeth do not show any affinity to this group. The radial wrin- kles and sulcations differ from those of any species I know of. In the only gravid specimen | have seen the marsupium pre- sented a peculiar striated, granular structure, different from that of any Naiad I know. It was narrowed in the middle, and produced into a sort of lobe behind, but, though the spec- imen seemed to be a perfectly normal one, | am in doubt wheth- er this peculiar form is constant. I do not think that this granulation is the result of a diseased condition. Genus ARKANSIA Ortmann and Walker, 1912. Arkansia ORYMANN and WALKER, Naut. XXV, 1912, p. 97. “Shell moderately thick, subrotund to subovate or subrhom- boidal, inflated, with full beaks. Disk sculptured with irreg- ular, oblique folds, which are sometimes indistinct. Beak sculpture poorly developed, consisting of two to three double- looped bars, the loops slightly swollen or tubercular, disappear- ing toward the disk and not continuous with the sculpture of the latter. Hinge well developed, with strong pseudocardinals, a very strong interdental projection in the left valve and well developed, strong, but rather short laterals. Soft parts: Supra-anal opening separated from the anal by a mantle connection, which is somewhat variable, but rather long (a little shorter to somewhat longer than the anal; the supra- anal is correspondingly longer or shorter ; in one case there 1s a double mantle connection). Mantle edges, between the anal and branchial, drawn together by the gill-diaphragm but not united. Inner edge of anal almost smooth, that of the branchial with papille. 478 ARKANSIA uter lamina of outer gills connected with mantle to its pos- terior end, and thus the gill-diaphragm is complete. Anterior end of inner gills located about midway between the posterior base of the palpi and the anterior end of the outer gills. Inner lamina of inner gills free from the abdominal sac, except for a short distance at the anterior end. Palpi of medium size, sub- falcate, their posterior margins connected for about one-thi -d of their length. Gills with well-developed septa and water-tubes. The septa are rather distant in the male and in the inner gill of the female. The outer gill alone is marsupial in the female, with very close septa. Edge of marsupium with slightly thickened tissue, indi- cating that it is capable of being stretched out when gravid. Type, Arkansia wheeleri Ortmann and Walker. ARKANSIA WHEELERI Ortmann and Walker. “Male and female shells alike. Shell subrotund to subovate or subrhomboidal, inflated, rather thick and solid ; dark reddish- brown or black, usually lighter toward the beaks, which in young shells are chestnut-colored ; epidermis with a silky lus- ter; beaks very prominent, projecting anteriorly and incurved over the large lunule, their sculpture consisting of two or three double-looped bars, the loops slightly swollen or tubercular ; sculpture restricted to the extremity of the beaks, the remain- der of the umbonal region being entirely smooth ; posterior half of the disk sculptured with irregular, oblique folds, sometimes nearly obsolete, which on the dorsal slope curve upwards, and in front of the posterior ridge are crossed by numerous, irreg- ular, radiating, small folds or wrinkles at right angle:. to the lines of growth; anterior portion of the disk smooth; unterior margin nearly straight in front of the beaks, then projecting in a regular curve, which continues around the basal margin until it meets the posterior margin at an obtuse angle about one-third up from the base; hinge margin nearly straight ; pos- terior margin slightly curved; posterior ridge not prominent, usually rounded, but sometimes obscurely biangulate; hinge complete ; pseudocardinals strong, ragged, in the left valve, ARKANSIA 479 two, not strongly differentiated and coalescing along the hinge line, the anterior narrow and parallel with the hinge line, the posterior somewhat wider and heavier and scarcely separated from a strong projection of the interdentum, which is contin- uous with the lower lateral and slopes gradually to its extrem- ity ; upper lateral low, the groove between them deep and ex- tending nearly to the beak; a single, strong pseudocardinz1 in the right valve with a deep pit behind it to receive the anterior pseudocardinal of the left valve, interdentum cut away to make room for the interdental projection in the left valve; a single strong, but rather short lateral ; ligament dark brown; muscle scars not very deep, those of the anterior adductor and pos- terior adductor large, those of the anterior retractor and pedal protractor rather small and inconspicuous ; cavity of the beaks very deep; nacre usually salmon-colored above the pallial line, bluish-white below (sometimes entirely white) and rather thin,. slightly iridescent with a wide, dark prismatic border. Length (of type) 73.5, height 62, diam. 41 mm.” (O. & W.) Arkansia wheeleri ORTMANN and WALKER, Naut., XXV, 1912, p. 98, pl. vu. “The shell characters of this fine species and most interesting addition to our fauna are very peculiar and can be compared only with Arcidens, to which genus, 4rkansia, undoubtedly, is the closest affinity. In general, the external appearance is quite similar, and in both the smaller series of radiating wrinkles and the curved folds of the dorsal slope are very much alike. But Arkansia is a much heavier and more inflated shell, with the beaks fuller, more projecting and more ancerior, and the strong, oblique folds, like those of Quadrula plicata, are pecu- liarly its own. It differs, also, entirely in the beak sculpture, which is comparatively simple and confined to the extremity of the beak, and is quite similar to that of certain Ouadrule. In hinge characters it differs in having strong, well-developed laterals. In the presence of the interdental process in the left valve and the cutting away of the interdentum in the right valve opposite it, it is related to both 4 rcidens and Symphynota. 480 SYMPHYNOTA The smallest specimen examined (in Mr. Wheeler's collec- tion), measures: length 35, height 33, and diam. 23 mm., being almost circular in shape, and looks, externally, very like a young, smooth Q. pustulosa Lea, the oblique folds being only slightly evident in the post-basal region, A very large spectmen, also in Mr. Wheeler’s collection, measures: length 87, height, 73, and diam. 48 mm. The structure of the soft parts agrees entirely with that of the subfamily 201: Baphia complanata H. and A. ApaAms, Gen. Rec. Moll, II, (857, p. 500. Margaritana complanata CALKtns, Pr. Ot. Acad., 1874, p. 46. Alasmodon complanatus SoweRsy, Conch. Man., 1842, p. 61, fig. 140.—Kuster, Conch. Cab. Unio, 1861, p. 199, pl. LXxv, ‘fig. 1.—Sowersy, Conch. Icon., XVI, 1866, pl. L, fig. 266. Complanaria gigas Sowrrsy, Conch. Man., 1839, fig. 141; 1842, p. 115, fig. 141. ? Megadomus gigas Swainson, Tr. on Mal., 1840, pp. 265, 378. 492 ALASMIDONTA Var. katherine (Lea). Shell much smaller than the ordinary manifestation of the species, irregularly elliptical or obovate and wanting the dor- sal wing. The epidermis is smoky-brown; the beaks in the specimens | have seen are so badly eroded that I cannot form any idea of their sculpture. It seems to be the arctic manifesta- tion of the species, which is so common in western rivers. Length 90, height 62, diam. 23 mm. Type locality, Lake Superior. Also Lake Winnipeg; Sagi- naw Bay, Michigan. Unio katherine Lua, Syn., 1838, p. 35; Tr. Am. Phil. Soc., VI, 1839, P- 143. Symphynota complanata var. katherine Stmrson, Syn., 1900, p. 666. One of the largest and most ponderous of the Naiades. The hinge is more solid and the form of the sheli is more rounded than the other species I have placed in Symphynota. But oc- casional specimens have hinges much like that of S. costata and shells drawn out so that they approach S. compressa in form. Genus ALASMIDONTA Say, 1818. Monodonta Say, Nich. Enc., U1, 1817. Alasmidonta Say, Jl. Ac. N. Sci. Phila., I, 1818, p. 459.—Orr- MANN, Ann. Car. Mus., VIII, 1912, p. 294. Alasmodonta Say, Nich. Enc., 3d ed., IV, 1810. Uniopsis Swainson, Tr. on Mal., 1840, p. 382. Shell generally rhomboid, inflated, with a well-developed posterior ridge, which ends in a point behind when it is single or a biangulation when double; beaks full and high, with coarse, concentric or slightly double-looped bars; epidermis rayed, shining; hinge with two pseudocardinals in the left valve and one in the right; laterals wanting or imperfect; cavity of the beaks deep; dorsal scars under the hinge plate ; nacre bluish. Animal with the marsupium occupying the entire outer gills ; eills rounded below, inner much the larger, united to the ab- dominal sac, or free; mantle generally having square spots on ALASMIDONTA 493 the posterior border ; branchial opening papillose ; anal opening smooth or crenulate. Type, Monodonta unduiata Say. Say first called his genus JZonodonca, but as that name was preoccupied he changed it to Alasmidonta. Later on he wrote the name Alasmodonta and this has been generally used by conchologists. The shells are generally more inflated than those of Symphynota, and the hinge of the right valve is not cut into behind the pseudocardinals as it is in that genus. In Alasmidonta the inner gills are united to the abdominal sac, while in Symphynota they are not united to it, a character, however, which is not to be greatly relied on. In the latter ge- nus the marsupium is thick and pad-like and the mantle is strongly attached at the pallial line. Key to species of Alasimidonta. Posterior slope of the shell corrugated. Shell solid, truncated behind, much inflated. A. marginata. Shell subsolid, elongated, A. raveneliana Shell thin, rather short. A. varicosa. Posterior slope not corrugated. Shell inflated. Solid with strong teeth, A. undulata. Thin, greatly inflated, rough and dark. A. arcula. Moderately inflated, smooth. A. triangulata. Shell scarcely inflated. Subsolid, dull, greenish, faintly rayed. A. minor; calceolus. Dull brownish, rayless or feebly rayed. A. holstonia; georgiana. Thin, sharply pointed behind. A. heterodon. Generally spinose. A. collina Subgenus ALASMIDONTA Ss. Ss. Shell ovate-rhomboid, solid, inflated, shining, with very strong, generally concentric, beak sculpture; pseudocardinals solid, stumpy, somewhat radiately ridged; laterals short, very imperfect, or wanting; beak cavities deep, compressed. 494 ALASMIDONTA Animal having the inner gills wider than the outer through- out; palpi long; marsupium loose and flabby, and having ova scattered throughout it in the only gravid specimen seen. ALASMIDONTA UNDULATA (Say). Shell elliptical or subrhomboid, subinflated, solid, inequi- lateral, with full, high beaks, whose sculpture consists of very strong ridges that run parallel with the growth lines; in front of and behind them there are often raised, radial threads ; pos- terior ridge wel! developed, rounded, ending behind generally below the median line; surface with uneven growth lines; epidermis yellowish-green to dark brown or blackish, painted with wide and narrow rays, which are in old shells visible only by transmitted light, usually shining; left valve with a strong tooth under the beak and a small one in front; right valve with one irregular tooth in front of the beak ; laterals almost want- ing. blurred; anterior scars impressed; beak cavities deep, compressed ; nacre bluish-white, purplish or salmon, thickened in front. Length 75, height 44, diam. 30 mm. length 70, height 47, diam. 32 mm. Length 50, height 30, diam. 19 mm. Lower St. Lawrence drainage; southward to North Caro- lina. Type locality, Delaware and Schuylkill Rivers. Monodonta undulata Say, Nich. Enc., 1817, pl. 1, fig. 3. Alasmidonta undulata Say, Jl. Acad. N. Sci. Phila., I, 1818, p. 460.—SIMPSON, Syn., 1900, p. 667. Alasmodonta undulata SAy, Nich. Enc., 1819, pl. mm, fig. 3. Alasmodon undulata Swainson, Tr. on Mal., 1840, p. 288, fig. 61.—GouLp, Inv. Mass., 1841, p. 115, fig. 76.—Dx Kay, Zool. of N. Y., Pt. 5, 1843. p.. 198,-pl xv, his. 227 Margarita (Margaritana) undulata Lea, Syn., 1836, p. 44; 1838, p. 27. Unio undulata HAniEy, Test. Moll., 1842, p. 211. Margaritana undulata Kuster, Conch. Cab. Unio, 1862, p. 208, pl. xcrx, fig. 4.—Gourp, Inv. Mass., 1870, p. 176, fig. 478.—HarTMAN and MicHeEner, Conch. Cest., 1874, p. 92, fig. T90. ALASMIDONTA 495 Margaron (Margaritana) undulata Lea, Syn., 1852, p. 42; 1870, p. 68. Mya undulata Woon, Ind. ‘Test. Rev., 1856; p. 199, pl. 1, supp., fig. 5. Baphia undulata H. and A. Apams, Gen. Rec. Moll., I, 1857, Pp. 499. P Unio undulatus Cariow and REeve, Conch. Nom., 1845, p. 65. Strophitus undulatus Stimpson, Shells of New Eng., 1851, p. iW ? Unio glabratus Sowrersy, Rec. and Foss. Shells, XVI, 1823, fig. Alasmodonta sculptilis Say, N. Harmony Diss., II, 1829, p. 339. Strophitus sculptilis Stimpson, Shells of New Eng., 1851, p- 15. Unio hians VALENCIENNES, Rec. Obs. Zool., II, 1833, p. 235, pl. Liv, figs. 2a, 2b. Untopsis radiata SwAINson, Tr. on Mal., 1840, p. 280, fig. 62. Uniopsis mytiloides Swainson, Tr. on Mal., 1840, p. 382, fig. 62. ? Unio swainsont SOwWERBY, Conch. Icon., XVI, 1868, pl. Lx xvi, fig. 396. Margaron (Margaritana) swainsoni Lea, Syn., 1870, p. 30. A characteristic species of the Atlantic drainage. Usually the shell is solid and shining, brightly rayed when young but becoming apparently a uniform brown or blackish when old, but showing rays when held up to the light. The beak sculp- ture is very coarse and there are sometimes radial wrinkles running across it. The teeth are stronger than in any other species, which I place in 4lasmidonta. The nacre varies much in color and is decidedly thickened in front. Subgenus PRESSODONTA Simpson, 1900. Pressodonta SIMPSON, Syn., 1900, p. 667. Shell decidedly rhomboid, surface generally painted with unbroken rays; beak sculpture slightly corrugated ; teeth com- pressed. Marsupium thick, smooth, pad-like. Type, Unio calceolus Tea. 496 ALASMIDONTA The names Hemiodon and Hemidonta were applied by Swainson to this group, but he used the first previously for a division of the Helicidz and the second is merely feminine of the first. He also used the name Hemidon, but whether it was intended for the group of Alasmidonta calceolus or the subfamily 4lasmodontine, | cannot determine. Group of Alasmidonta calceolus. Shell small, subsolid, rhomboid, inflated, rayed but not shin- ing; beak sculpture varying from strong concentric bars to irregular corrugations, sometimes faintly doubly looped, and with fine radiating ridges in front and behind; pseudocardinals rather solid; laterals very faint; marsupium occupying the whole of the outer gills, thick, pad-like; inner gills wholly or partly free from the abdominal sac; mantle bordered with square, black spots. ALASMIDONTA CALCEOLUS (Lea). Shell rather small, convex to subinflated, usually decidedly rhomboid, somewhat inequilateral, subsolid ; beaks neither full nor elevated, the sculpture varying from strong bars, which run parallel with the growth lines to irregular, often doubly looped, corrugations, generally with radial, raised threads in front and behind; posterior ridge usually high, rounded and ending in a rounded point behind at the base of the shell, rarely it ends just below the median line; surface with uneven growth lines; epidermis dull ashy or ashy-green with wavy rays, sometimes the dark rays occupy most of the shell leav- ing narrow light rays between; left valve with a blurred tooth under the beak and a faint one in front; right valve with one tooth in front of the beak; laterals blurred, often almost want- ing; nacre whitish, a little thicker in front. Length 50, height 30, diam. 22 mm. Length 36, height 22, diam. 15 mm. Upper Mississippi drainage; Ohio, Cumberland, and Ten- nessee rivers; Trower and Middle St. Lawrence systems. Type locality, Ohio. ALASMIDONTA 497 Unio calceolus Vea, Tr. Am. Phil. Soc., ITI, 1830, p. 265, pl. meme +) Obs, 1, 91634, p.. 7 -pl iv, fig. 1—Cuenu, Mil. Conch., 1858, pl. vin, figs. 2, 2a, 2c.—KuSTER, Conch, Cab. Unio, 1861, p. 187, pl. L1x, fig. 3. Strophitus calceolus Conran, Pr. Ac. N. Sci., Phila., VI, 1853, p. 262. Unio calceola DesHAyEs, An. sans Vert., 2d ed., VI, 1835, p. 546.—Hantey, Biv. Shells, 1843, p. 212, pl. xxu, fig. 29.— Sowrrey, Conch. Icon., XVI, 1868, pl. LXxvu1, fig. 410. Margarita (Margaritana) calceola Lea, Syn., 1836, p. 455 1838, D277. Margaron (Margaritana) calceola Lea, Syn., 1852, p. 43; 1870, p. 68. Margaritana calceola Kuster, Conch. Cab. Unio, 1862, p. 299, pisxcre gO: Baphia calceola H. and A. ApAms, Gen. Rec. Moll., II, 1857, p. 500. Alasmidonta calceola Simpson, Syn., 1900, p. 668. Alasmodonta truncata Conrap, New F. W. Shells, 1834, p. 73- Margarita (Margaritana) deltoidea Lia, Syil.~no30, ps 44s E333, Po-27.- Margaritana deltoidea Lea, Tr. Am. Phil. Soc., VI, 1838, p. 43; pl. xm, fig. 38; Obs., II, 1838, p. 43, pl. xt, fig. 38.— CuEnu, Man., 1859, II, p. 144, fig. 711.-—Kuster, Conch. Cab., 1862, p. 2990, pl. xcix,, fig. 5- Unio deitoidea Hantey, Biv. Shells, 1843, p. 211, pl. xxi, fig. 50. Margaron (Margaritana) deltoidea Lma, Syme, 1O52,, p. 42 5 1870, p. 67. Strophitus deltoidea Conran, Pr. Ac. N. Sci., Phila., VI, 1853, Pp. 203: Baphia deltoidea H. and A. Apams, Gen. Rec. Moll., II, 1857, p. 499. Alasmodonta deltoidea BAKER, Moll. Chicago, Pt. 1, 1898, p. 63, pl. vi, fig. 2; vu, fig. 4. Unio deltoideus SowrRBy, Conch. Icon., XVI, 1868, pl. LXXvI. fig. 395- 498 ALASMIDONTA [ cannot by any possibility separate this from Lea’s Mar- garitana deltoidea. lea says that the deltoidea is smaller, more triangular and flattened and that the undulations of the beaks are unbroken. ‘There seems to be every possible varia- tion between these extremes of beak sculpture, sometimes oc- curring in a lot from the same locality ; the larger shells have both kinds of sculpture and while the form is usually decid- edly rhomboid, there occurs every variation to specimens that are nearly elliptical. ALASMIDON'TA MINOR. (Hea). Shell small, rhomboid, convex, somewhat inequilateral, with moderately full but not high beaks, their sculpture a few coarse ridges running parallel with the growth lines, with radial threads in front of and behind them; posterior ridge low or moderate, rounded, ending behind in a widely rounded point at the base; surface with uneven growth lines; epidermis greenish-vellow with broad and narrow wavy green rays, the yellow spaces between them often narrower than the rays, the whole lusterless; left valve with a strong, double or triple tooth; right valve with one strong tooth under the beak ; lat- erals faint and blurred; nacre bluish-white, sometimes dirty straw-colored, a little thicker in front. Length 39, height 25, diam. 14 mm. Length 37, height 22, diam. 15 mm. ‘fennessee and Cumberland River systems. Type locality, North Carolina. Margaritana minor Lea, Pr. Am. Phil. Soc., IV, 1845, p. 166; Tr. Am. Phil. Soci, X, 1848, p. 82, ‘pl. vir, fis. 267 Obs. EV, 1848, p. 56, pl. vin, fig. 26—CuHeENv, Man., 1859, II, p. 144, fig. 713. Strophitus minor Conran, Pr. Ac. N. Sci. Phila., VI, 1853, p.. 263. Margaron (Margaritana) minor, Lea, Syn., 1852, p. 42; 1870, p: 67: Baphia minor H. and A. Anams, Gen. Rec. Moll., II, 1857, p- 490. Alasmidonta minor StmMpson, Syn., 1900, p. 668. ALASMIDONTA 499 ] think it more than likely that this will prove only a mere variety or local race of 4. calceolus, when a sufficient amount of material is examined. It seems to be quite rare, and I have never been able to see more than a few shells from the Tennes- see and Cumberland systems. The posterior ridge is a little lower and more rounded than in 4. calceolus and the posterior point is more widely rounded; the epidermis is a little differ- ently colored, the lighter part of it being yellowish instead of ashy. Group of Alasmidonta heterodon. Shell small, rather thin, rhomboid; beak sculpture very strong, consisting of concentric ridges or irregular corruga- tions, often slightly doubly looped and swollen on the well- developed posterior ridge; surface rayed; pseudocardinals compressed, reflexed; laterals single, double, or triple in each valve. Animal with branchial opening having a few coarse papille ; anal opening smooth, or with very fine crenulations. ALASMIDONTA HETERODON (Lea). Shell small, long rhomboid, inequilateral, convex, thin to subsolid; beaks low but rather full, their sculpture consisting of a few strong, corrugated ridges, which run nearly parallel with the growth lines, with radiating threads in front of and behind them; posterior ridge well developed, narrowly round- ed or subangular, ending in a rather sharp point a little above the base; surface with uneven growth lines, dirty greenish, faintly raved, dull colored; left valve with two pseudocar- dinals, the hinder somewhat broken and compressed; right valve with one compressed pseudocardinal ; laterals imperfect, lamellar, one or two, sometimes three in each valve; nacre bluish-white. Nength 36, height 18, diam. 12 mm. Northern New England to Virginia. Type locality Schuylkill River and Derby Creek, Pa. 500 ALASMIDONTA Unio heterodon Lea, Tr. Am. Phil. Soc., III,1830, p. 428, pl. vill, fig. 11; Obs., 1, 1834, p. 42, pl. vu, fig. 11—ConRaD, Monog., X, 1838, p. go, pl. xix, fig. 3—HAaANLeEy, Biv. Shells, 1843, p. 183, pl. xx1, fig. 42,—CueEnu, Ill. Conch., 1858, pl. xvi, figs. 2, 2a, 2b.—KustEr, Conch. Cab., 1861, p. 192, pl. LXL, fig. 2.—Sowersy, Conch. Icon., XVI, 1866, pl. XXxv, fig. 184—Harrman and MicHenrer, Conch. Cest., 1874, p. OI, fig. 188. Margarita (Unio) heterodon Lea, Syn., 1836, p. 18; 1838, p. LO. = Margaron (Unio) heterodon La, Syn., 1852, p. 24; 1870, p. 30. Alasmidonta heterodon SiMPSON, Syn., 1900, p. 669. This shell closely resembles specimens of A. calceolus, but is more delicate and elongated, and is generally more com- pressed. The pseudocardinals are often quite imperfect and generally a little reflexed; the laterals are lamellar and not perfectly developed, often varying in number. ALASMIDONTA DIVERSA (Conrad). Shell rhomboid, considerably inflated, thin, but thicker be- fore, especially at the base, inequilateral ; beaks moderately full, their sculpture not seen; posterior ridge well developed, end- ing in a rounded point at the base of the shell; epidermis yel- lowish-olive, clouded with dark brown; rays obsolete or want- ing ; left valve with a three-parted, compressed pseudocardinal ; right valve with one compressed pseudocardinal ; laterals dou- ble in the right valve and single in the left; nacre greenish or wax-colored, dirty white towards the anterior base. Length 38, height 24, diam. 18 mm. Type locality, Shoal Creek, North Alabama. Unio diversus SoNRap, Am. Jl. Sci., X XI, 1856, p. 172 (fig. in outline). Alasmidonta diversa Stmpson, Syn., 1900, p. 669. Conrad has only given a couple of outline figures of this shell and I have never seen it. He states that it bears a remarkable ALASMIDONTA 501 resemblance to Unio heterodon. It is however more regularly rhomboid, higher, more inflated than that species and different- ly colored. Group of Alasmidonta collina. Shell rhomboid, subsolid, with beak sculpture consisting of strong, concentric bars, sometimes slightly doubly looped, and swollen on the low, posterior ridge; often with one or more small spines on the disk in front of the posterior ridge; epi- dermis brown, rayless or feebly rayed; rest marks well de- fined: teeth rather compressed ; laterals lamellar. Animal unknown. ALASMIDONTA COLLINA (Conrad). Shell rhomboid, convex, subsolid, inequilateral, with mod- erately full, high beaks, their sculpture a number of strong, slightly double-looped ridges; posterior ridge full, rounded, ending behind at the base of the shell in a rounded point ; growth lines elevated into slight, concentric ridges; besides this sculpture there are generally one or two sharp, prominent tubercles or spines placed on a line running from the beaks to a little behind the central base, though these are sometimes en- tirely wanting ; epidermis smoky, greenish-brown, showing the rest marks, subshining ; left valve with two subcompressed, ir- regular pseudocardinals and two straight, delicate laterals ; right valve with a compressed pseudocardinal, with a vestigial one in front of and behind it, with one lateral; beak cavities shallow: nacre bluish-white, slightly thicker at the anterior base. Length 35, height 22, diam. without the spines 13, diameter over all 15 mm. North Carolina and Virginia. ‘Type locality, North River, Va. Unio collinus Conrap, Monog., VIII, 1837, p. 65, pl. XXXVI, fig. 2; XII, 1840, p. 109, pl. 1x, fig. 3—HANLey, Biv. Shells, 1856, p. 382, pl. xx, fig. 57—Kuster, Conch. Cab. Unio, 1861, p. 188, pl. ux, fig. 5—Sowerry, Conch. Icon., XVI, 1866, pl. xLIx, fig. 263. 502 ALASMIDONTA Margaron (Unio) collinus Lua, Syn., 1852, p. 23; 1870, p. 35 Alasmidonta collina Simrson, Syn., 1900, p. 669. I have never seen the animal of this species and cannot be certain as to its systematic position. The form of the shell, and the beak sculpture, are like those of forms of Alasmidonta. The teeth, though nearly or quite perfect, are more like those of that genus than of any Unios I know of. They are only s little better developed than those of 4. heterodon. wr Group of Alasmidonta holstonia, Shell subsolid, beak sculpture rather strong, decidedly dou- bly looped, surface brownish, slightly rayed; pseudocardinals delicate ; laterals nearly or quite wanting. Animal like that of A. calccolus. ALASMIDONTA HOLSTONIA (Lea). Shell usually long rhomboid, rarely elliptical, subsolid, con- vex, inequilateral; beaks full but not high, their sculpture strong, doubly-looped ridges, the hinder loop narrow and an- gular; posterior ridge rounded or disposed to be double, end- ing behind in a rounded point or feeble biangulation at the base; surface with irregular growth lines; epidermis dull ereenish-brown or yellow-brown, rarely with slight rays; left valve with two low, compressed teeth in front of the beak; right valve with a single, compressed anterior tooth; laterals nearly or quite obsolete; nacre bluish-white. Length 50, height 29, diam. 19 mm. Tennessee River system; headwaters of the Coosa River. Type locality, Holston River. Margaritana holstonia Laas, Tr. Am. Phil. Soc., VI, 1838, p. 42, plo x11, fe. 37; Obs.; LL, 1838 sp: war pl. Sait, ie a7- Margarita (Margaritana) holstonia Lea, Syn., 1836, p. 46; 1838, p. 28. Margaron (Margaritana) holstonia Lea, Syn., 1852, p. 44; 1870, ‘pi 70; Strophitus holstonia Conrapv, Pr. Ac. N. Sci. Phila., VI, 1853, p. 2623. ALASMIDONTA 503 Paphia holstonia H. and A. Apams, Gen. Rec. Moll., II, 1857, Pp. 499- Alasmidonta holstonia Simpson, Syn., 1900, p. 670. Unio. holstonianus HANLEY, Biv. Shells, 1843, p. 213, pl. XxuL, fig. 44.—-Sowerey, Conch. Icon., XVI, 1868, pl. Lxxv1, fig. 308. Margaritana holstoniana Kuster, Conch. Cab. Unio, 1862, p. 202, pl & ie. 4: ? Unio striatus Sowerry, Conch. Icon., XVI, 1868, pl. LxXxvuill, ng. 407. A small species without any striking characters. It looks so much like a member of the vanwxremensis group of Lamp- silis that it has often deceived experts and has been sent out as Unio litus, U. proprius, etc., but a glance at its interior will always show the lack of laterals, which are present in the other species. Group of Alasmidonta georgiana. Shell rhomboid, slightly rayed, with strong beak sculpture, the ridges parallel with the growth lines ; pseudocardinals sin- gle, in each valve; laterals wanting. ALASMIDONTA GEORGIANA (Lea). Shell elliptical, convex, rather thin, inequilateral, beaks al- most compressed, not elevated but pointed, their sculpture con- sisting of a few rather coarse ridges, which run nearly paral- lel to the growth lines; posterior ridge full, rounded, ending behind in a rounded point below the median line; growth lines irregular; epidermis dirty yellowish-green with a few narrow rays behind or rayless; left valve with a low, smooth, compressed tooth just in front of the beak ; right valve with a single compressed tooth placed well forward ; laterals reduced to mere vestiges; nacre bluish or purplish, dirty and lurid. Length 53, height 30, diam. 17 mm. Type locality, Etowah River, Georgia. Also Tennessee. Margaritana etowahensis LEA, Pr. Ac. Nat. Sci. Phila., I, 1858, p. 138; Jl. Ac. Nat. Serebiila.[V, 1850, -p. 227, pl Xxx1, fig. 110; Obs., VII, 1859, p- 45, pl. XXX1 fig. 110. 504 ALASMIDONTA Margaritana (Alasmodonta) ctowahensis Ciessin, Conch. Cab. Ano.; 1875, poeperae. Lot, Nes 1S: Margaritana etowahensis Payrri, Conch. Sam., III, 1890, p. 1. Margaritana georgiana Lea, Pr. Ac. Nat. Sci. Phila., II], 1859, p. 280. Margaron (Margaritana) georgiana Lia, Syn., 1870, p. 68. Alasmidonta georgiana SIMPSON, Syn., 1900, p. 670. Alasmodonta impressa ANTHONY, Am. Jl. Conch., I, 1865, p. Ee. PUA eae 7 llea has three specimens in his collection, which he calls Mergaritana georgiana. ‘The type and a young shell are no doubt the same thing, but the best preserved shell is, I feel sure, a young Symphynota quadrata. It has decidedly and sharply doubly-looped beak sculpture and better developed teeth than the others. The two specimens of georgiana have badly eroded beaks, but by a careful examination with a glass I can make out that their sculpture is coarse, nearly straight ridges. . Their teeth consist of a single rounded knob in each valve; the laterals are wanting. Subgenus RuGIFERA Simpson, 1900. Rugifera SIMPSON, Syn., 1900, p. 670. Shell elongated, rhomboid, inflated, surface brilliantly paint- ed with radiations, which often break into a dappled or splash- ed pattern of color; posterior slope slightly corrugated ; teeth very imperfect ; laterals wanting. Animal with a thick, smooth, pad-like marsupium. Mantle with square spots behind. Type, Alasmodonta marginata Say. ALASMIDONTA MARGINATA Say. Shell medium to rather large, long rhomboid, nearly or quite equilateral, subsolid to solid, subinflated ; beaks very full, high, sculptured with a few strong corrugations, which show a ten- dency to be doubly looped; posterior ridge very high and angled, ending behind in a point at the base of the shell, behind AY,ASMIDONTA 505 the ridge there is a decided oblique truncation and the trun- cated area is rather finely corrugated; growth lines uneven; epidermis smooth, shining, greenish, ashy or smoky-green with narrow yellowish rays and broken, clouded green ones; left valve with one small, compressed, sharp tooth in front of the beak; right valve with a small anterior tooth; laterals almost or quite wanting; beak cavities rather deep; nacre white or bluish, sometimes straw-color, rarely reddish or pur- ple; prismatic border distinct. Length 120, height 72, diam. 48 mm. Length 10g, height 58, diam. 45 mm. Upper Mississippi drainage ; Ohio, Cumberland, and Ten- nessee River systems; Michigan; Upper St. Lawrence drain- age. Type locality, Scioto River, Chillicothe, O. Alasmodonta marginata Say, Nich. Encyc., 1819, No. 1; Jl. Ac. Nat. Sci. Phila., I, 1819, p. 459—RAFINESQUE, Ann. Gen. Sci. Brux., V, 1820, p. 317. Margarita (Margaritana) marginata Lea, Syn., 1836, p. 43; 1838, p. 27. Margaron (Margaritana) marginata Lea, Syn., 1852, p. 423 1870, p. 67. Margaritana marginata Kuster, Conch. Cab. Unio, 1862, p- AG, le CUR Mee. 3. Alasmodonta marginata BAKER, Moll. Chicago, Pt. 1, 1808, p. 62, pl. rv, fig. 4; vil, fig. 7; xxu1, fig. 3. Margaritana marginata var. truncata B. H. Wricut, Naut., XT, 1898, p. 124. Unio marginatus Sowrrry, Conch. ‘Icon., XVI, 1800, ‘ple aay fig. 207. Alasmodonta truncata Conrap, Pr. Ac. Nat. Sci. Phila., Vee 1853, p. 262. Alasmidonta truncata Supson, Syn., 1900, p.,671. In rare instances the beaks of this species are as near to oT nearer to the posterior end than to the anterior. Occasionally the tooth in the left valve is divided and both are often a little 506 ALASMIDONTA reflexed. I have seen old, solid shells, which seemed to have a rayless, nearly black or brown epidermis, but when held up to the light the rays could be seen. ALASMIDONTA VARICOSA (Lamarck ). Shell of medium size, thin, long rhomboid, with moderately full, slightly elevated beaks, their sculpture consisting of heavy ridges that run nearly parallel to the growth lines; posterior ridge high, generally double, ending in a biangulation near the base of the shelf, the greatest inflation being along this ridge; posterior slope slightly corrugated, remainder of the surface irregularly marked with growth striz ; epidermis dirty yellowish-green with feeble, sometimes clouded, rays; left valve with a faint tooth under or a little in front of the beak; right valve with an anterior tooth; laterals wanting; nacre bluish, lurid in the cavities with a distinct, narrow prismatic border. Length 54, height 32, diam. 20 mm. Lower St. Lawrence; southward in streams draining into the Atlantic to South Carolina. Type locality, Schuylkill River near Philadelphia, Pa. Unio varicosa L.AMARCK, An. sans Vert., VI, 1819, p. 78. Alasmidonta marginata SIMPSON, Syn., 1900, p. 670. Alasmodon marginata Goutp, Inv. Mass., 1841, p. 116, fig. 77. —-Ds Kay, Zool. of N. Y., Pt. v. 1843, p. 196, pl. x1v, fig. Bam Unio marginata HANEY, Biv. Shells, 1843, p. 211, pl. xx1, fig. ye Anodonta marginata C. B. ApaAms, Thompson’s Hist., 1842, p. 164. Baphia marginata H. and A. Apams, Gen. Rec. Moll., IT, 1857, Pp. 500. Margaritana marginata Goutp, Inv. of Mass., 1870, p. 177, fig. 479.—HartMaAn and MicHenrr, Conch. Cest., 1874, p. 93, fig. IOI. Unio marginatus Carrow and Reeve, Conch. Nom., 1845, p. 6r. Unio cariosa 1.AMARCK, An. sans Vert., VI, 1819, p. 80. ALASMIDONTA 507 ‘Alasmodon corrugata DE Kay, Zool. of N. Y., Pt. 5, 1843, p. 198, pl. xxv, fig. 259. Mya rugulosa Woon, Ind. Test., 3d ed., 1856, p. 199, pl. 1, supp. fig. 7. Certainly distinct from the heavier, larger, more inflated and truncated form found in western rivers. The teeth are less developed and it is biangulate behind. Specimens oc- casionally grow somewhat larger than the measurements given above. ALASMIDONTA RAVENELIANA (I,ea). Shell oblong, subrhomboid, scarcely inflated, thin to sub- solid, inequilateral; beaks moderately full, slightly elevated, their sculpture apparently a few strong, somewhat doubly- looped bars; posterior ridge double, ending behind at or near the base in a biangulation ; posterior slope having fine corrugat- ed, radiating wrinkles; surface otherwise generally smooth or marked with a few uneven growth lines; epidermis pale yel- lowish-green to brown, faintly rayed, the rays sometimes brok- en into blotches; each valve has a single, low, smooth tooth near the beaks; laterals almost or quite obsolete; nacre dirty greenish, whitish or purplish, lurid; prismatic border distinct. T,ength 76, height 39, diam. 23 mm. Length 75, height 42, diam. 37 mm. Tennessee and Cumberland River Systems. Type locality, French Broad and Swannanoa rivers, N. C. Margaritana raveneliana Lea, Tr. Am. Phil. Soc., V, 1834, p. 106, plexver hee so; Obs., 1.1834, ps 218, pl) xvi, hg. 50.— iusime Conch. Cab. Unio, 1862, p: 207; pl: xcix, fig. 2: Alasmodonta ravencliana Frrussac, Guer. Mag., 1835, p. 26. Margarita (Margaritana) raveneliana Lea, Syn., 1836, p. 44; 1O30! p: 27: Margaron (Margaritana) raveneliana Lea, Syn., 1852, p. 42; 1870, p. 68. Baphia raveneliana H. and A. Apams, Gen. Rec. Moll., II, 1857, p. 500. Alasmidonta raveneliana Stmpson, Syn., 1900, p. 671. 508 ALASMIDONTA Strophitus ravenelianus CONRAD, Pr. Ac. Nat. Sci. Phila., VJ 1853, p. 263. Unio swananoensis HANiEY, Test. Moll., 1842, p. 211; Biv. Shells, 1843, p. 211, pl. xx111, fig. 39. Lea's material is in almost unrecognizable condition. But the National Museum possesses fine sets of the species from Asheville, North Carolina, and from the North and South Forks of the Cumberland River. None of these specimens have perfect beaks, but one or two, which are less eroded than the rest, seem to indicate that their sculpture consists of strong, wavy, slightly doubly-looped ridges. Old shells appear to be uniform brown, but show the rays when held up to the light. It is a larger, solider, more elongated shell than what I have described as A. waricosa and is less solid and inflated, less trun- cated behind and more biangulate than marginata. Bullella Simpson, Syn., 1990, p. 672. Shell thin. greatly inflated, somewhat triangular, with a high, sharp posterior ridge; beaks very full, having exceedingly ‘strong, concentric sculpture, extending well on to the disk; pseudocardinals reflexed, compressed: Animal with the gills large, nearly semicircular below, inner the larger, united the whole length to the abdominal sac ; man- tle border with square spots. Type, Margaritana arcila Lea. ALASMIDONTA ARCULA (Lea). Shell subtriangular, thin, greatly inflated. slightly imequi- lateral, with very full, high beaks, their sculpture consisting of a number of strong ridges running nearly parallel with the growth lines. ‘These extend well out on to the disk and they are crossed by fine, wrinkled, radiating threads. In front of and behind the regular sculpture there are radiating lire. Posterior ridge very high, angled, ending behind in a point near the base; posterior slope truncated, with a low, radial ridge: anterior end much narrowed, rounded. the beaks rising ALASMIDONTA 509 high above it; surface with strong, uneven growth lines, cov- ered with a dull epidermis, which is greenish and slightly rayed in young shells; in the adult state it is apparently black, but the rays can be seen through it when it is held up to the light ; hinge line sinuous; left valve with a iong, compressed, imperfect tooth at the beak, which is partially divided; right valve with one compressed, triangular tooth: laterals almost obsolete; beak cavities very deep; nacre bluish, bluish-white and thickened in front. Length 80, height 60, diam. 50 mm. Altamaha River, Georgia. Type locality, Altamaha River, Liberty Co., Ga. Margarita (Margaritana) arcula Lea, Syn., 1836, p. 43; 1838, pe27: Margaritana arcula Lea, Tr. Am. Phil. Soc., VI, 1838, p. 71, pla sxe Oo Obs. lly 1836... 71, pl. xoc11,. fig! 69.— CHENU, Man., 1859, II, p. 144, fig. 712. Unio arcula HANLEY, Biv. Shells, 1843, p. 210, pl. Xxu, fig. 49. —Sowersy, Conch. Icon., XVI, 1866, pl. xivin, fig. 250. Margaron (Margaritana) arcula Lea, Syn., 1852, p. 42; 1870, Dp. 67. Alasmodonta arcula ConrAD, Pr. Ac. N. Sci. Phila., VI, 1853, p. 262. Baphia arcula H. and A. ApAms, Gen. Rec. Moll., II, 1857, p. 500. Margaritana (Alasmodonta) arcula Ciesstx, Conch. Cab. AMO LO7O, Pp 272, pl: EXKXIM, figs, -7, °8. Alasmidonta-arcula SIMPSON, Syn., 1900, p. 672. A remarkable form, which cannot be mistaken for any other. If the character of the longitudinally folded gravid outer gills is constant the species should have generic rank, but I am not so sure that itis. A. triangulata seems to stand between it and the other Alasmidontas. ALASMIDONTA TRIANGULATA (Lea). Shell short, subtriangular, inflated, rather thin, slightly in- equilateral; beaks high and full, their sculpture a number of strong, concentric ridges with radial lire in front of and be- 510 ALASMIDONTA hind them; posterior ridge high and angled, ending behind in a point near the base; posterior slope somewhat truncated, having two or three low, radial ribs and a few feeble plications ; surface rather smooth; epidermis tawny to ‘greenish-brown, smoky, faintly rayed; left valve with one irregular tooth under the beak, with a vestigial one forward; right valve with a high, recurved anterior tooth; laterals almost obsolete; beak cavities deep ; nacre bluish-white. Length 40, height 27, diam. 24 mm. South Carolina amd Georgia. Type locality, Upper Chattahoochee River; Columbus; Pa- lato Creek, Ga.; Sawney’s Creek, S. C. Margaritana triangulata Lea, Pr. Ac. N. Sci. Phila., II, 1858, p. 138; Ji. Ac. N..Sci..Phila., LV, 1859,.p..226, pl. xxaaaene, 111; Obs., VII, 1859, p. 46, pl. xxxu, fig. 111.—KUSTER, Conch. Cab. Unio, 1862, i303) pl. c; fis... Unio triangulata Sowerby, Conch. Icon., XVI, 1868, pl. LXxx, fig. 414. Margaron (Margaritana) triangulata Lea, Syn., 1870, p. 68. Margaritana triangulatus Pare., Conch. Sam., III, 1890, p. 174. Alasmidonta triangulata SIMPSON, Syn., 1900, p. 672. This species shows relationship to 4. arcula by its inflation, its triangular form, beak sculpture and beaks and the some- what sinuous hinge plate. But the hinge is heavier and more like that of the ordinary Alasmidontas than that of arciwa and the epidermis is that of an Alasmidonta. Unfigured and indeterminate species. Margaritana ectowahensis Conran, Pr. Ac. Nat. Sci. Phila., IV, 18409, p. 154. Alasmodon (Decurambis) atropurpureum RA¥FINESQUE, Cont. Monog., 1831, p. 5. Alasmodon(Decurambis)scriptum RArInEsoue, Cont., Monog.. 1S31, jh 5- Alasmodon (Lasmicona) viridis RAFINESQUE, Cont., Monog., 1935s ps 5 MARGARITANA 511 Alasmodon (Sulcataria) papyraceum RaA¥inEsgur, Cont. Monog., 1831, p. 5. Alasmodon {(Sulcataria) badium RaFinrsgur, Cont. Monog., 130, cpa 5: Alasmodon (Amblamodon) hians RAFINESQUE, Cont. Monog., [O30 p25: Genus MARGARITANA Schumacher, 1817. Baphie MruscHEN, Mus. Gevers, 1787, p. 472. Unio Rerztus, part, Diss. Hist. Nov. Test. Gen., 1788, p. 16. Unio OKEN, Lehrbuch der Nat., 1815, p. 236. Margaritana SCHUMACHER, Essai Nouv. Syst., 1817, p. 137. Damalis (1aiacH manuscript) Gray, Pr. Zool. Soc. Lond., 1847, p. 196. Baphia H. and A. Apams, Gen. Rec. Moll., II, 1858, p. 499. Shell elongated, usually arcuate, rounded in front, almost lacking a posterior ridge: beaks rather low, the sculpture con- sisting of a few coarse, parallel ridges, which follow the growth lines; epidermis concentrically striate, brownish or blackish ; hinge teeth generally imperfect or not fully developed; two more or less perfect pseudocardinals in the left valve, and one in the right, often reduced to mere tubercles ; behind these the hinge plate is narrow and rounded for some distance ; laterals short, usually imperfect or wholly wanting ; cavity of the beaks rather shallow ; muscle scars large, those of the anterior rough- ened, posterior elliptical; nacre generally more or less covered inside the pallial line with small muscle scars. Animal with very long gills, inner wider in front, free for the greater part of their length from the abdominal sac, the two pairs united to their posterior ends, which project back- ward for some distance, unconnected with the mantle; palpi ‘very large, falcate, united half way posteriorly; branchial opening having crowded, often arborescent, papilla arranged in folds; anal opening smooth or crenulate ; superanal opening 512 MARGARITANA not closed below ; marsupium occupying the entire outer gills. oot and abdomen small; whole animal dark colored. Type, Mya margaritifera Linnzeus. A\ homogeneous group having a circumboreal distribution with two species in the warmer temperate region of the United States and one, singularly isolated, in the Oriental Tropics. Most of the species have shells with defective hinge teeth and in none of them are they very strongly developed. All have simple, more or less arcuate, shells with dull colored, thick, dark epidermis, and ‘gills that are free from the mantle at the posterior end. -I have examined a great many animals of the Margaritana margaritifera taken at different seasons and in many localities but have never found one gravid. Von Wahl states that the marsupium occupies the entire outer gills, and I have been informed that specimens have been found with a few embryos in the inner gills also. The name Baphie Meuschen has precedence, but was never described; it was applied to a miscellaneous lot of bivalves, and is in the plural number. Retzius’s first species in Unio, the type of a section without laterals, is the (J. margaritifer, but in 1792 Bruguiére in Choix de Mémoires, I, p. 106, fully and carefully redefined the genus Unio, restricting it to species with cardinal and lateral teeth. Ortmann, (Naut. XXV, 1911, p. 6), separates this genus from the Unionide and proposes the family Margaritanide for its reception. “The chief differences of this family are found in the incomplete gill-diaphragm ; in the entire lack of a tendency to approach or to unite the mantle margins to form siphons; in the structure of the gills, which lack regular septa running parallel to the gill-fhlaments, and, consequently, in the lack of the well-defined water-tubes (ovisacs in the female): in the marsupium being formed by all four gills ; and in the small size and globular shape of the glochidium, without true hooks.” But Lefevre and Curtis, (Bull. Bur. Fish. XXX, 1912, p. 118), consider this “a procedure of doubtful wisdom.” MARGARITANA 513 Kry TO SPECIES OF MARGARITANA. Posterior end of the shell corrugated. M. hembeli. Shell not corrugated. Pseudocardinals strong. Laterals generally wanting. M. margarttifera. Laterals present. Shell large, solid. M. crassa. Shell rather small, thin behind. M. laosensis. Pseudocardinals feeble. Shell long, not compressed, arcuate. M. monodonta. Shell rather short, compressed. M. decumbens. Group of Margaritana margaritifera. Shell having irregular, concentric growth lines, but without plicate or corrugated sculpture. MARGARITANA MARGARITIFERA (Linnzus). Shell large, much elongated, usually arcuate, rounded be- fore and somewhat so behind, rather solid, inequilateral, not inflated ; beaks low, not inflated, their sculpture consisting of longitudinal ridges, which are sometimes a little broken; pos- terior ridge moderate or low, often having a wide, radial de- pression above it, and ending below the median line, some- times in a point, in old shells in a rounded termination ; surface with rude growth lines; epidermis thick, blackish or brown- ish, often subshining; left valve with two stumpy pseudocar- dinals ; right valve with one pseudocardinal ; laterals generally wanting; beak cavities not deep; muscle scars impressed, the anterior rough, the posterior elliptical; nacre lurid, bluish- white, whitish, purplish or purple, generally showing pits where the mantle is attached, often having dark blotches. Length 152, height 65, diam. 40 mm. Length 122, height 60, diam. 38 mm. Length 110, height 54, diam. 35 mm. All Europe except the southernmost portion; northern Asia; - Japan; northern North America; Iceland. Its southern limit 514 MARGARITANA seems to be about north latitude 40°. It appears to be entirely circumboreal, except that, so far as is known, it is missing in the central part of the North American continent. Wetherby has suggested that it may have been destroyed in this region by the ice of the glacial epoch. But, see Walker, Pr. Mal. Soc. London, IX, 1910, p. 126. It is found in the upper Mis- souri and in Canada East, New York and the New England States. Mya margaritifera Lister, Hist. Anim. Ang. App., 1685, pl. Lesko shi Hist. Conch., 1685, pl. cx1iix, fig. 4.—LInNzus, Systema. Nat., roth ed., I, 1758, p. 671.—Da Costa, Hist. Nat. Brit., 1778, p. 225, pl. xv, fig. 33.—KNorr, Vergn., IV, 1769, pl. xxv, fig. 2—PENNANT, Brit. Zool., IV, 1777, pl. XL, fig. 18.—Da Costa, Hist. Nat. Brit., 1778, p. 225, pl. xV, fig. 3.—ScHrRO6TER, Fluss Conch., 1779, p. 168, pl. rv, fig. 1.—Donovan, Brit. Shells, III, 1801, pl. _Lxx111.—Woop, Gen. Conch., I, 1815, p. 107, pl. xx1m1, figs. 1-3; Index Test., 1825, p. 12, pl. u, fig. 30—CuHENU, Bib. Conch., Ist ser., I, 1845, p. 57, pl. xx, figs. 1, 2—Haniry (Woop), Ind. Test., 3d ed., 1856, p. 16, pl. 11, fig. 30. Mya margaritifera testa ovali oblonga, etc.—CHEMNI‘z, Conch: Cab Vi, 1762, pe 15,.pl. Bele 5. Baphie margaritifera Mruscuin, Mus. Gevers, 1787, p. 472. Unio margaritifera DRAPARNAUD, Hist. Moll. Fr., 1806, p. 132, pl. x, figs. 17-19; pl. x1, fig. 5?-—C. Prrirrer, Nat. Deutsch. Land und Suss. Moll., 1821, Pt. 1, p. 115, pl. v, fig. rv. Margaritana margaritifera SCHUMACHER, Essai. Nouv. Syst., I, 1817, p. 124, pl. x, fig. 4—TroscHet, Arch. fiir Naturg., XIII, pl. 1, 1847, p. 270, pl. mv, fig. 1—Moguin-TANpDon, Hist. Moll. Fr., 1855, p. 623, pl. xxu, figs. 14-16—KusTkEr, Conch, Cab., 1856, p. 293, pl. XXXVIII; XXXIX, figs. 2-4.— Cuenu, Manual, 1859, II, p. 144, fig. 710 —HartMAN and MrcHENer, Conch. Cest., 1874, p. 91, fig. 189.—CLEssSIN, Deutsch. Fx. Moll., 1876, p. 440, fig. 293—Srmpson, Syn., 1900, p. 674.—ORTMANN, Ann. Car. Mus., VIII, 1912, p. 230, fig. 1. MARGARITANA yes) Alasmodonta margaritifera Conrad, New F. W. Shells, 1834, Baye: Margarita (Margaritana) margaritifera Lea, Syn., 1836, p. 45; 1838, p. 28. Margaron (Margaritana) margaritifera Lea, Syn., 1852, p. 43; 1870, p. 60. Baphia margaritifera H. and A. Apams, Gen. Rec. Moll., II, 1857, p. 499; III, pl. cxvu, figs. 2, 2a. Unio margaritiferus Revzrus, Dis. Hist. Nat., 1788, p. 16— _ Turton, Conch. Ins. Brit., 1822, p. 241, pl. xv1, fig. I.— Turton, Man. L. and F. W. Shells, 1831, p. 19, fig. 9.— _ Forers and Hanzey, Hist. Brit. Moll., II, 1853, p. 146, pl. XXXVIM.—Sowe_rsy, Ill. Ind. Brit. Shells, 1859, pl. viz, No. 1. mere ate, ej aud. WV Moll> Brit.,.1866, ple 111, fig. 15 =— Sowersy, Conch. Icon., XVI, 1868, pl. Lxrv, fig. 325. Alasmodon margaritiferus Brown, 1, and F. W. Conch., ~ 1836, p. 112, pl. xx1, fig. 13; pl. xxu, figs. 1-3—Brown, Ill. Recent Conch., 1844, p. 83, pls. xxx, figs. I-4; XXxXI, figs. 1, 2; XXxII, figs. 13-15.—Turton, Man. L. and F. W. Shells, 1857, Pp. 277, pl. 11, fig. 9. Margaritana margaritiferus WrESTERLUND, Faun. Pal., II, Pt. 7, 1890, p. 184. Alasmodon margaritiferum Fieminc, Hist. Brit. Moll., 1828, p. 417. Unio margaritifer var. minor RossMASSLER, Icon., Pt. 2, 1835, p19; plo, fies120; Unio margaritifer Kuster, Conch. Cab., 1856, p. 130, pls. XXXVIII, XXxXIX.—MoguIn-Tanpon, Moll. Terr. et Fluv. Fr., II, 1855, p. 566, pl. xnvir—NorpENSKIOLD and Ny- LANDER, Fin. Moll., 1856, p. 86, pl. v1, fig. 74.—Drourr, Nay. Fr., II, 1857, p. 57, pl. 1—Hesstine, Perl. und Ihre Perlen, 1859, p. 86, pl. 1—Rererve, L. and F. W. Moll. Brit.; 1863, p. 223, fig. 3:—L. Apams, Coll. Man., 1884, p. 19, pl. 1, fig. 12. Unio (Margaritana) margaritifer ScuRENCK, Reis. and F. im Amur-Lande, II, 1867? p. 7o0. Unio elongata L.AMARcK, An sans Vert., VI, 1819, p. 70. Damaris elongata IeAcH, Syn. Moll. Gt. Brit., 1852, p .322. 516 MARGARITANA Margaritana elongata Locarp, Coq. de Fr., 1893, p. 149, fig. 162. Unio elongatus Sowersy, Conch. Icon., XVI, 1868, pl. Lxxv1, fig. 307. Alasmodonta arcuata Barnes, Am. Jl. Sci., VI, 1823, p. 277, pl. xu, fig. 20.—C. B. Apams, Thompson’s Hist. of Ver- mont, 1842, p. 165, fig.; F. W. and L. S. of Vt., 1842, p. 165, fig. Mya arcuata Earoy, Zool. Text Book, 1826, p. 222. Alasmodon arcuata Gout, Inv. of Mass., 1841, p. 113, fig. 75. —De Kay, Zool. of N. Y., Pt. 5, 1843, p. 197, pl. xiv, fig. 224. Margaritana arcuata Kuster, Conch. Cab., 1856, p. 293, pl. XXxXIx, fig. 1—Goutp, Inv. of Mass., 1870, p. 174, fig. 477. Unio sinuata C. Pretrrer, Nat. Deutsch. L. and S. W. Moll., Pt. 2, 1825, p. 33, pl. vil, fig. 4. Unio roissyi MicHaup, Comp. Hist. Moll. Fr., 1831, p. 112, pl. XVI, fig. 28. Margaritana roissyi WESTERLUND, Faun. Pal., II, Pt. 7, 1890, p. 186. Unio tristis Moreier, Moll. Portugal, 1845, p. 107, pl: xi fig. 2. Margarita (Unio) crassissimus Lea, Syn., 1836, p. 40; 1838, p. 26. Unio (Alasmodonta) dahuricus MinpEnporrr, Bull. Phys. Math. Ac. St. Petersb., IX, 1850, p. ?; Sib. Reise, II, 1851, p. 275, pl. xxv1, figs. 3-5. Unio dahuricus MippenvorrF, L,. and S. Moll. Sib., 1859, p. 26. Unio (Margaritana) dahuricus SCHRENCK, Reis. und Forsh. Amur-Lande, II, 1867, p. 699. Margaritana dahurica Kove, Faun. Jap. Ext., 1879, p. 143, pl. xix, gs. 1, 2 Alasmodon falcata Goutp, Pr. Boston Soc. Nat. Hist., III, 1850, p. 294.—-U. S. Expl. Exp., XII, 1852, p. 433, figs. 545, 5454, 545 b. Unio falcatus Sowrerny, Conch. Icon., XVI, 1868, pl. UXxv, fig. 390. MARGARITANA 517 Margaritana margaritifera falcata Day, Alaska, XIII, 1905, p- 132.—HANnniBAL, Pr. Mal. Soc. London, X, 1912, p. 122. Unio (Alasmodonta) complanatus MipvpeNvorrr, Sib. Reise, DS 1S51; Pt. 1, pl 273; oe svu, figs. 1-6. Margaritana complanata WESTERLUND, Faun. Pal., II, Pt. 7, 1890, p. 187. Unio mongolicus MippENvorFF, Sib. Reise, II, 1851, p. 277, pla Xm BS. 75.8. Alasmodon yubaensis TRAsk, Pr. Cal. Acad. Sci., I, 1855, p. 30. ? Margaritana raveneliana CuENU, Man., 1859, II, p. 144, fig. 714. This species has the widest distribution of any Naiad in the world. It is found throughout Europe excepting, perhaps, the extreme southern portion, in Northern Asia, Japan, West- ern North America south to below the fortieth degree of lati- tude and east of the Rocky Mountains in the upper Missouri River. It seems to be missing in the North Central part of North America, but is abundant in Eastern Canada, New York, Pennsylvania and New England. I have examined extensive series of this shell, including the Lea, the Jeffreys and the general collections of the National Museum, some thousands in all, and I am unable to separate the species into satisfactory varieties. Usually the laterals are nearly or quite wanting in adult specimens ; but occasionally they are quite well developed and I have seen full grown shells from Massachu- setts, the Western United States, Japan and Europe with very fair laterals. In the young shells they are often developed. In localities where food is abundant and conditions are favor- able the shells are large, clean, comparatively high and straight, the base being full, and this development has received names in Europe, but it occurs throughout the range of the species. Other specimens, which have not had abundant food or favor- able environment, are small, stunted and decidedly arcuate. Old shells often become arcuate, as is the case among many Naiades. Among the shells of the Western United States the nacre is often deep purple or sometimes salmon red. I 518 MARGARITANA have never seen this kind of nacre in specimens from other parts of the area of distribution of the species, but I do not think such a variation worthy of a varietal name. MARGARITANA CRASSA (Retzius). Shell large, solid, arcuate, sometimes subrhomboid, often rounded in front and behind, inequilateral, not inflated, beaks moderately elevated but not full; surface with irregular growth lines ; epidermis btackish in old shells, brownish-green or red- dish-brown in younger ones, dull; left valve with one or two strong, irregular, ragged pseudocardinals and two, sometimes three remote, rather small laterals; right valve with a single pseudocardinal, sometimes with a vestigial tooth behind it, and one lateral; beak cavities moderately deep; muscle scars large, impressed, the anterior rough, the posterior smooth and elliptical; pallial line deep, often rough; nacre white, showing pits occasionally of the muscular attachment of the mantle. Length 137, height 67, diam. 40 mm. Length 126, height 69, diam. 33 mm. Length 134, height 63, diam. 38 mm. Southern Europe; possibly into Asia Minor and southwest Siberia. Mya testa crassa SCHROTER, Flussconch., 1779, p. 182, pl. 0, fig. 2. Margaritana crassa Simpson, Syn., 1900, p. 677. Unio crassus Rerzius, Diss. Hist. Nat., 1778, p. 17. Margaron (Unio) crassus Lea, Syn., 1852, p. 39; 1870, p. 62. Unio auricularius SPEUGLER, Skriv. Nat. Siesk., 111, 1792, p. 54. Unio rugosa Porrer, Coq. Fluv., et Terr. de l’Aisne, 1801, p. 54- Unio sinuata Lamarck, An. sans Vert., VI, 1819, p. 70.— 3LAINVILLE, Man., 1825, p. 539, pl. Lxvul, fig. 3—DESHAYES, Enc. Meth., II, 1827, p. 151, pl. ccx1vit, fig. 1; II, 1830, p. 679; pl. CEXLVinly HS. AL; a, Os Unio (Potamida) sinvata Swatnson, Tr. on Mal., 1840, p. 268. MARGARITANA 519 Unio sinuatus RossMASSLER, Icon., III, 1836, p. 22, pl. x1, fig. 195.—Dupuy, Hist. Moll. Fr., 1852, p. 630, pl. xx1u1, fig. 7-—RossMASSLER, Icon., III, 1854, p. 38, pl. Lxx, fig. 853. —Moguin-Tanpon, Moll. Terr. and Fluv. Fr., II, 1855, p. 567; LII, pl. xvi, figs. 1-3—Drover, Nay. Fr., II, 1857, p. 61, pl. 1.—Sowersy, Conch. Icon., XVI, pl. yxu, fig. 311. —Locarp, Coq. de Fr., 1893, p. 151, fig. 164. Margaritana simuata ORTMANN, Naut., XXV, IQII, p. 6. ? Unio litoralis C. PreiFFER, Nat. Deutsch. L. and S. W. Moll., Pt. Wlezk pial; pl. v, ie. 12: Unio crassissimus Hantey, Biv. Shells, 1843, p. 209, pl. RIT, fig...54. Unio gargotte Puiiirpi, Moll. Sic., 1836, p. 66.—RossMass- LER, Icon., VII and VIII, 1838, p. 26, pl. xxxv, fig. 493. The shells of this species bear a strong superficial resem- blance to those of MJargaritana margaritifera, the latter having been repeatedly mistaken for this form. Usually the epider- mis is duller and blacker than that of margaritifera, the beaks are a little fuller and higher, while the nacre is always white and the laterals are fairly well developed. The muscle scars are much alike in the two species, the anterior ones being rough and the posterior ones regularly elliptical, but in WW. crassa the scars of attachment are few or often wanting, while they are generally present and often numerous in margaritifera. The M. crassa appears to be confined to Southern Europe, and, judging by the scarcity of specimens in collections, it is a rather rare species. Unio batavus, with which it has been con- founded, is a much smaller and rather more inflated species, which has its metropolis north of that of WW. crassa. Retzius’ description is in Latin, and consists of ten words, and as-he does not figure the species, it would be impossible to determine what he meant only for the fact that he refers to the Flussconchylien of Schroter (Mya testa crassa, p. 182, pl. u, fig. 2). Schroter’s figure is not a very good one, but I can have no doubt that he had before him the large, heavy, black Naiad, with lateral teeth, found in southern Europe. In general it closely resembles the M. margaritifera externally, 520 MARGARITANA but the epidermis is more dull black, the beaks are usually higher and more strongly developed, the nacre is white, and it has fairly well-developed laterals. European conchologists. seem to have quite commonly mistaken heavy, large forms of Unio batavus for Retzius’ species, and in a number of cases the M7. margaritifera has been taken for it. Ortmann, (1. c.), follows Kobelt, (Nachr. Bl. D. Ges., 1909, p. 43), in referring Unio crassus Retz. to the species commonly known as Unio batavus. Haas, (Nachr. Bl. D. Ges., 1910, p. 181), has recently made this species the type of a new genus, Pseudunio, but, apparent- ly, without sufficient reason. MARGARITANA LAOSENSIS (Lea). Shell elongated, arcuate, rather solid, not inflated, inequilat- eral; beaks slightly elevated, not full, their sculpture consist- ing of ridges that nearly follow the growth lines; posterior ridge high, very wide and rounded; anterior end of the shell rounded, posterior end a little wider, rounded or feebly point- ed; surface with rude, concentric growth lines; epidermis brownish-green or greenish-brown and subshining in young shells, brown or blackish and dull in old ones; left valve with two small, stumpy pseudocardinals, the anterior one often al- most obsolete, and two remote, small laterals ; right valve with two psendocardinals, the hinder rudimentary and one lateral ; laterals granular and showing traces of vertical striation ; mus- cle scars well impressed, the anterior ones rough, the posterior elliptical; nacre whitish or purplish, thickened in front, gener- ally showing small pits. Length 90, height 37, diam. 22 mm. Laos Mountains, Cambodia; Siam; Burma. Unio laosensis Lea, Pr. Ac. Nat. Sci. Phila., VII, 1863, p. 190; ji. Ac. N. Sei: Phila.,- V1,°2866, py xx he. wor; Ops. 1867, p. 67, pl. xx1, fig. 61—Sowegrsy, Conch. Icon., XVI, 1866, pl. xiv, fig. 256. Margaron (Unio) laosensis Lea, Syn., 1870, p. 62. Margaritana laosensis Stmpson, Syn., 1900, p. 678. MARGARITANA 521 Margaritanopsis laoensis, HAAS, Con. Cab., Unio, 1910, pl. xn, ngs. T, 2. Unio sula ‘TuEoBALD (where?) Smaller than margaritifera, with a higher and much wider posterior ridge and always having laterals. The nacre is much clearer than that of margaritifera. An undoubted Margari- tana notwithstanding its peculiar geographical distribution. Haas has recently, (Nachr. Deutsch. Mal. Ges., 1913, p. 33), made this species the type of a new genus, Margaritanopsis. ‘ MARGARITANIA MONODONTA (Say). Shell greatly elongated, arcuate, sometimes subinflated, in- equilateral, subsolid to solid; beaks a little elevated but not in- flated, their sculpture consisting of strong, straight ridges running parallel with the growth lines; posterior ridge full, curved and ending behind at the base of the shell in front of the hinder end; anterior and posterior ends rounded; surface sculptured with rude growth lines; epidermis greenish-brown and subshining in the young shell, blackish, thick and dull in old shells; pseudocardinals imperfect, generally reduced to a single imperfect spur or low tubercle in each valve of the old shells ; laterals blurred and feeble; there are usually two in the left valve and one in-the right; nacre white, granular and pitted; muscle scars impressed, the anterior ones rough, the posterior elliptical. Length 172, height 53, diam. 38 mm. Ohio; Cumberland, and Tennessee river systems; Illinois; eastern lowa; Nebraska? Type locality, Falls of the Ohio and Wabash River. Unio monodonta Say, N. Harm. Diss., II, 1829, p. 293.—Say, Am. Conch., I, 1830, pl. 1v.—CueEnu, Bib. Conch., Ist. ser., Ui, 3845, p: 12; pleat, figs 1 Alasmodonta monodonta FeRussac, Guer. Mag., 1835, p. 20. Margaritana monodonta Conrap, Pr. Ac. N. Sci. Phila., VI, 1853, p. 262.—SiMpson, Syn., 1900, p. 679.—ORTMANN, Ann. Car. Mus., VIII, 1912, p. 233, figs. 2, 2a. Cumberlandia monodonta OrTMANN, Naut., XXVI, 1912, p. £3. 522 MARGARITANA Unio monodontus Say, Am. Conch., VI, 1834.—Han ey, Biv. Shells, 1843, p. 210, pl. xx111, fig. 48.—IXustrEer, Conch. Cab., LSO1, DP) 221, Di BRK, HE, I: Margarita (Unio) monodontus Lia, Syn., 1836, p. 40; 1838, p. 20. Margaron (Unio) monodontus Lea, Syn., 1852, p. 39; 1870, p. 62. Unio soleniformis Lea, Tr. Am. Phil. Soc., [V, 1831, p. 87, pl. x, fig. 175 Obs., I, 1834, p. 97, pl. x, fig. 17—CuHeEnu, III. Conch., 1858, pl. xiv, figs. 4, 4a, 4b; Manual II, 1859, p. 137, fig. 661.—SoweRsBy, Conch. Icon., XVI, 1866, pl. x.y, fig. 243. Margaritana soleniformis Parte, Conch. Sam., 1890, p. 173. The anterior end of old shells is often much more solid than the posterior. Longer in proportion than any other Margari- tana. Dr. Ortmann (1. c.) has recently made this species the type of a new genus, Cumberlandia, which he separates from Mar- garitana on account of the greater development of the gill structure. He says: “While in other species of the genus Margaritana the interlaminar connections of the gills are scat- tered, and irregularly distributed, or fall into more or less dis- tinct oblique rows, in the present species these irregular, inter- rupted rows are developed as continuous septa, which run obliquely forwards. In the middle of the gills these septa are well developed and quite continuous, but rather distinct from each other. Towards the ends of the gills they are more irreg- ular, shorter and chiefly at the posterior end they are somewhat interrupted, and thus it is clearly seen that they represent a further development of the oblique, interrupted rows present in other species of Margaritana.” Group of Margaritana decumbens. Shell trapezoidal, thin, compressed, pointed at the posterior base; hinge line sinuated. MARGARITANA DECUMBENS (Lea). Shell irregularly rhomboid or trapezoid, being narrowed in front and somewhat widened behind, compressed, scarcely subsolid, inequilateral, somewhat arcuate; beaks neither full MARGARITANA 523 aor high, their sculpture not made out; hinge line sinuous, be- ing incurved in front of the beaks; posterior ridge angulated, ending in a point behind at the base of the shell; surface with rude, uneven growth lines, brownish or yellowish-green, faint- ly rayed, dull and dirty ; left valve with an imperfect, somewhat double pseudocardinal, and two feeble, curved laterals; right valve with two small pseudocardinals and an imperfect lateral ; anterior scars slightly roughened; posterior scars elliptical ; nacre purplish-tinted, rather bright, with a few pits. Length 84, height 42, diam. 18 mm. Type locality, Alabama. Umo decumbens Lea, Pr. Ac. N. Sci. Phila., V, 1861, p. 40; [iP AcaN: Sci Phila, 1862,.p: 87, pl xi, fie 236; Obs:, VIII, 1862, p. I, pl. xu, fig. 236.—Sowersy, Conch. Icon., XVI, 1868, pl. LXXxil, fig. 432. Margaron (Unio) decumbens Lea, Syn., 1870, p. 62. Margaritana decumbens Simpson, Syn., 1900, p. 679. Quite different from the other species, yet having the char- acters of a Margaritana. It is a little strange that only the type is known of this curious compressed, rather thin, trape- zoidal species. Group of Margaritana hembeli. Shell having its posterior part more or less corrugated. MARGARITANA HEMBELI (Conrad). Shell oblong, obovate to subrhomboid, sometimes a little arcuate, subsolid to solid, inequilateral ; beaks moderately full, their sculpture not seen; posterior ridge low, rounded or some- what double; anterior end rounded or subtruncate; posterior end feebly pointed below the median line and sometimes an- gled at the base; surface with rude, uneven growth lines ; pos- terior end with more or less distinctly marked corrugated sculp- ture, often divaricately plicate; epidermis tawny-brownish or blackish ; left valve with two low, stumpy, rough pseudocardi- nals and two remote, feeble laterals; right valve with one pseu- 524 MARCARITANA docardinal and behind it a vestige of a second with one lateral ; laterals granular with traces of vertical striation ; muscle scars impressed, the anterior rough, the posterior elliptical; nacre whitish or lurid purplish with numerous pits. Length 110, height 52, diam. 33 mm. Length 83, height 40, diam. 22 mm. Louisiana; Burnt Corn, Alabama. Type locality, New Orleans, La.? Unio hembeli Conrapv, Monog., X, 1838, p. 93, pl. L1, fig. 1.— HAN tery, Biv. Shells, 1856, p. 383, pl. xxv, fig. 3.—Sow- ERBY, Conch. Icon., XVI, 1866, pl. xxx111, fig. 172. Margaron (Unio) hembeli Lea, Syn., 1852, p. 21; 1870, p. 32. Margaritena hembeli Simpson, Syn., 1900, p. 679.—ORTMANN, Ann, Car. Mus., VIII, 1912, p. 235, figs. 3, 3a. The general form and texture, the teeth and scars in the cavities of the valves show this to be a Margaritana rather than an Unio. I have examined the animal, which is dark and has the posterior ends of the gills free as is that of M. margariti- fera. Specimens from Burnt Corn, Alabama, are strongly, cor- rugately plicate on the posterior slope and from the posterior ridge fainter radial ridges sweep forward and downward. Some of the shells from near New Orleans are almost smooth. —— —_—. i ll I » ill 2 Sh N\ N <= ~ RAR I ES SMITHSONIAN _ INSTITUTION NOILOLILSNI_ 53 1YVvVUusi w a ws - ul “. ee oc = wx <5 e ON 5 2 5 2 = Ww = = = = _ aN WW re — - SOE: - b a SN z Bs z a RARITIES SMITHSONIAN INSTITUTION NOILALILSNI NVINOSHLINS S31uVvuslt AN ~ WSS Ss NLILSNI_ NVINOSHLIWS NYINOSHLIWS ON! 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