ON MOLLUSCA OF THE WEST COAST OF NORTH AMERICA. 569 



7. Orbicida ostreoides, Lam.,= O. Norvegica, Sby. (non Lam.) + 0. striata, Sby. + 

 Crania radiosa, Gld. + O. \Discina'\IEvansii,'D&\. ? N.W.Africa. "The 

 locality, 'Bodegas, Cal.,' given by Mr. D. with O. Evansii, on Mr. Cuming's 

 authority, must, I think, oe a mistalfe." [The genua has not been found 

 on the Califomiau coast by any American collector.] 

 8 Venu^* grata, Sby. ,-\- tricolor, Shy. Gulf of Mexico, Mus. Cum. [^■=Tapes 

 grata, Say, Panama. The locality-labels have probably been misplaced. 

 These specimens are undoubtedly from the West Coast, nor has any 

 authority appeared for the species in the Atlantic. The Gulf of Mexican 

 " analogue " is T. granidata. The forms are intermediate between Chione 

 and Tapes.'] 

 9. Venus mtdticostata, Sby. Bay of Panama, in coarse sand at low water, Cuming. 

 " Probably = F'.iesi!e)-«,var.,with ribs more tumidly thickened androunded." 

 [The West Coast shells are distinguished by the very slight crenulation 

 of the ribs at the sides.] 



19. Verms asperrima, Sby. Guaoomayo, Centr. Am., sandy mud, 13fms., Cuming. 

 •' A form oi pcctorina ; shell of lighter substance, broader and more de- 

 pressed ; sculpture more elevately and definitely latticed." [This is the 

 shell named oj Mr. Cuming V. cardioides. Lam., and should take that 

 name, as prior to Sby.'s, if really distinct from pectorina. Also from 

 Panama. Mus. Smiths.] 



22. Venus discors, Sby., jun. St. Elena and (jiuacomayo, Centr. Am., sandymud, 

 6-9 fms., Cuming. " Concentric decussating ridges cease abruptly at the 

 posterior third.'' [Character very variable, even in the type-specimens ; 

 = T. grata, Say, var.] 



25. Vc/nis pectorina, Lam., p. 344,+ V. cardioides, Lam. Cenlr. Am., Miis, Cum. 



[Probably Atlantic : much heavier and stumpy ; sculpture coarser ; teeth 

 more like casi/ia, whorcas cardioides, no. 19, has a long anterior tooth 

 like siigillata f J 



26. Venus cimpdata, 'L&\-a..,=pulicaria, Brod. W. Columbia, Cuming. [= V. 



Finacatensis, Sloat, MS. in Mus. Smiths. Guaymas. The peculiar 

 smoothing-ofF of the central sculpture in the adult may be varietal. It 

 is improbable that Lam. was acquainted with the species.] 



S3. Venus C7-enulata, Chera., = crenata, QmA. W. L = F. ea;«Wa, Phil.,+ F. cre- 

 nifera, Sby.,+ ^'. Partemina, D'Orb. [Not to be confounded with the 

 V. crenifera, Maz. Cat. : has a small Cyprinoid lateral tooth, but no 

 radiating ribs near luiiule, nor long anterior tooth t.] 



35. Venus Califurniemis, Brod.,= V. lettcodon, Sby. Guaymas, Gulf Cal., sandy 

 mud, low water, [teste] Cuming. Mus. Cum. [= V.crassa, Sloat, MS. ju 

 Mus. Smiths. Not V. Califorma.na., Uonr.,= F'. simillima, Sby. This 

 species, with V. neglcc/a, compta, &e., having the mantle-bend nearly 

 obsolete, approach Anomalocardia subimbricata, and with that species 

 form a natural group, differing from the typical Venus as Lioconcha does 

 from Callista:^ V. succiiicfa, Val.] 



41. Venus Kennerkyi, Cpr., MS. % in Mus. Cum. Sab.—? [Puget Sound, 

 • Kennerley.] , 



43. Venus sugillata, Rve. California, Mus. Curtt. Characterized by the shining 

 purple umbos, finely latticed sculptm-e, dark-stained lunule and liga- 

 mentary area. [=" ^'- crenifera, Sby., teste Rve.," Maz. Cat. no. 105, 

 in aU essential characteis. Differs in the long anterior tooth being still 



* Through the kindness of Mr. Eeeve, with, a view to the completion of this Eeport, 

 I was enabled to compare the figured specimens in this genus with the text, and witli 

 the shells of the Smithsonian collection, before they were distributed. The bracketed notes 

 in the text are based on this examination. They are given with urusual detail, because 

 of the unique opportunity of throwing st>me light on a confessedly difficult family. 



t The characters of the teetli and pallial line frequently afford satisfactory diagnostic 

 marks between critical species, which are often oTerlooked by monographers. 



J The descriptions of Dr. Kennerley's shells had long been written, and would have 

 been published but for thp American wnr. The locahties of all the West Coast shells sent 

 from ttiB Smiths. Coh to Mr. Cuming were duly marked in the accompanying catalogues, 



55 



