658 pi;ar /:/: in \i;s or Tin: \ATIO\AL 



Animal with the outer gills larger than the inner behind, narrower in 

 front, inner free from the abdominal sac, all united to the mantle nearly 

 to their posterior points ; mantle double edged ; branchial opening large, 

 a lew irregular, large and small branched papilla. 1 on it; anal opening 

 large, with rudimentary papilla 1 ; superanal opening closed a long way 

 below; foot very large when living. No ova were found in the 

 branchiae in numerous specimens taken at different dates and localities. 



f GONIDEA ANGULATA Lea. 



Anodonta angiilnta LEA, Tr. Am. Phil. Soc., VI, 1838, p. !>7, pi. xvi, fig.52; *Obs., 

 II, 1838, p. 97, pi. xvi, fig. 52. *TROSCHEL, Arcb. fiir Nat., V, 1839, Pt. 2. p. 

 239. *HANLEY. Test. Moll., 1842, p. 222; *Biv. Shells, 1843, p. 222, pi. xxiv, 

 fig. 15. * GOULD, U.S. Expl.Exp., XII, 1852, p. 436. * CONRAD, Pr. Ac. Nat. 

 Sci. Phila., VI, 1853, p. 263. *H. and A. ADAMS, Gen. Rec. Moll., II, 1*57. p. 

 504. * CIIENU, Man., 1859, II, p. 146, fig. 722. *RKKVE, Elein. Couch., II, I860, 

 pi. xxxi. fig. 180. CLESSIN, Conch. Cab. Ano., 1874, p. 150, pi. LIII, figs. 3, 4. 

 * B. H. WRIGHT, Check List, 1888.* P.ETEL, Conch. Sam., Ill, 1890, p. 176. 



Margariia (Anodonta) anf/itldta LEA, Syn., 1838, p. 32. 

 *Marqaron (Anodonta) aiiyuluta LEA, Syn., 1852, p. 52; 1870, p. 83. 

 ' Anodon angulata CALTOW and REEVE, Conch. Norn., 1845, p. 66. 

 - Auodon angulatns SOWERBY, Conch. Icon., XVII, 1867, pi. in, fig. 6. 



. I nodon feminalis GOULD, Pr. Bost. Soc. N. Hist., Ill, 1850, p. 293 ; * Otia Conch., 

 1862, p. 87. 



Anodonta feminalis GOULD, U. S. Expl. Exp., XII, 1852, p. 436, figs. 547, 547^, 

 547&. *H. and A. ADAMS, Gen. Rec. Moll., II, 1857, p. 502. * P.ETEL, Couch. 

 Sam., Ill, 1890, p. 179. 



Anodonta randalli TRASK, Pr. Cal. Ac. N. Sci., I, 1855, p. 29. * P^ETEL, Conch. 

 Sam., Ill, 1890, p. 177. 



Anodon bian;/iilata SOWERHY, Conch. Icon., XVII, 1869, pi. xxni, figs. 8, 8a, 86. 

 *Anodon1a bianyulata CLESSIN, Conch. Cab. Ano., 1876, p. 234, pi. i.xxvn, fig. 3. 



Central California; north to British Columbia; east to Idaho. 



Genus ANODONTOIDES Simpson (in Baker) 1898. 

 (Type, Anodonta ferunsaciana Lea.) 1 



Anodontopsis SIMPSON (in Baker), Tr. St. Louis Ac. Sci., VIII, 1898, p. 76; not 



Anodontopsla McCoY. 

 Anodontoides SIMPSON (in Baker 1 ), Moll. Chicago, 1898, p. 72. 



Shell elliptical, inflated, thin, with a faint- posterior ridge, sometimes 

 constricted at the center of the base; beaks rather full, with a few 

 coarse, subparallel, concentric ridges, which are curved up rather 



1 The shells of this group are much like those of Strophitus, but have different beak 

 sculpture. The character of the marsupia is also different in the two genera. In 

 this group a limited number of ovules was found in the inner gills of one of the few 

 gravid specimens seen, while in Anodonta only the outer gills contain ova so far as 

 I have observed. It differs from Anodonta in the curving in of the hinge line in 

 front of the beaks, in the beak sculpture, and in having papillte on the anal open- 

 ing. Notwithstanding the fact that I have found embryos in all four gills of a 

 specimen of this genus, I have placed it with the Homogense rather than with the 

 Tetragena3 because the characters of shell and animal seeui to agree better with the 

 former than with the latter. 



