660 PBOCEEDIXC* or THE \.lTHi.\.IL 



Conch. Cab. Ano., 1*75, p. 210, pi. i.xiv, ti^s. 4, 5. ' B. H. WRICH r, Check 

 List, 1888. * P.ETEI,, Couch. Sain.. Ill, 1890, p. 178. 



on (Auodonta) dcnif/rata LKA, Syu., 1852, p. 50; 1870, p. 79. 



* \Anodonta oblita LEA, Tr. Am. Phil. Soc., X, 1-52, p. 290, pi. xxvm, fig. 52; 



* Obs., V, 1852, p. 46, pi. xxvm, fig. 52.* COXRAD, Pr. Ac. Nat. Sci. Phila., VI, 

 1853, p. 264. * II. and A. ADAMS, Gen. Rec. Moll., II, 1857, p. 502. *<.'LI:-SIN-, 

 Con<-h. Cab. Ano., 1875, p. 165, pi. LIV, figs. 7, 8. * B. H. WHKMIT, Check List, 

 1888. 



*Margaron (Anodonta} oblita LKA, Syn., 1852, p. 50; 1870, p. 79. 



*Anodon subctjllndracea SOWEKBY, Couch. Icon., XVII, 1867, pi. xiv, fig. 47. 



* Anodonta subcylindracea CLESSIN, Conch. Cab. AUG., 1873, p. 92, pi. xxvi, figs. 6, 7. 



tANODONTOIDES FERUSSACIANUS var. SUBCYLINDRACEUS Lea. 



* t Anodonta subcylindracea LEA,Tr. Am. Phil. Soc., VI, 1838, p. 106, pi. xxiv, fig. 117 ; 



* Obs., II, 1838, p. 106, pi. xxiv, fig. 117. *TROSCHEL, Arch, fiir Nat., V, 1839, 

 Pt. 2, p. 239.* HANLEY, Test. Moll., 1842, p. 223; * Biv. Shells, 1843, p. 223. 



* STIMPSON, Shells of N.Eng., 1851, p. 15. * CONRAD, Pr. Ac. Nat. Sci. Phila., 

 VI, 1853, p. 264." H. and A. ADAMS, Gen. Rec. Moll., II, 1857, p. 503.* LATCH- 

 FORD, Tr. Ottawa F. N. Club, 1882,p. 55.* B. H. WRIGHT, Check List, 1888. 

 *P.*:TI-:L, Conch. Sam., Ill, 1890, p. 185. * WALTON, Moll. Monroe Co., 1892, 

 p. 17, pi. vin, fig. 3. 



* Margarita (Anodonta) subcylindracea LEA, Syn., 1838, p. 32. 



* Anodon subcylindracea DE KAY, Zool. of N. Y., Pt. 5, 1843, p. 200, pi. x vi, fig. 229. 



. * CATLOW and REEVE, Couch. Norn., 1845, p. 68. 



*Harflaron (Anodonta) subcylindracea LEA, Syn., 1852, p. 51; 1870, p. 82. 

 *Anodontoide8 xubcylindraceus BAKER, Moll. Chicago, Pt. 1, 1898, p. 74, pi. iv, fig. 

 4; vi, fig. 1. 



ANODONTOIDES FERUSSACIANUS var. MODESTUS Lea. 



* t Anodonta modesta LEA, Pr. Ac. Nat. Sci. Phila., 1857, p. 84; *J1. Ac. Nat. Sci. 



Phila., IV, 1860, p. 364, pi. LXIII, fig. 189; *Obs., VIII, 1860, p. 46, pi. LXIII, fig. 

 189. 'CLESSix, Conch. Cab. Ano., 1874, p. 153, pi. XLIX, figs. 7, 8. *B. H. 

 WRIGHT, Check List, 1888. * P.ETEL, Conch. Sam., Ill, 1890, p. 182. 

 *Margaron (Anodonta) modesta LEA, Syn., 1879, p. 79. 

 Anodon modestus SOWERBY, Couch. Icon., XVII, 1867, pi. x, fig. 26. 



Mississippi drainage area generally; St. LawrenceKiver system; Eed 

 River of the North; Saskatchewan liiver; Connecticut. ? The varieties 

 are found in the St. Lawrence system. 



Genus PEGIAS Simpson, 19OO. 

 (Type, Margaritana fabula Lea.) 



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 biaugulate and trun- 

 cate behind; beak sculpture consisting of subconcentric corrugations, 

 generally swollen on the posterior ridge; epidermis decorticated, but 

 showing a few dark, radial rays on the base of the shell; pseudocardi- 

 nals rather solid; laterals 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. 



