K0.1312. SYNOPSIS OF THE YEN ETUI). E-B ALL. 401 



PSEPHIDIA LORDI Baird, 1863. 



Port Etches, Prince AVilliam Sound, Alaska, and southward to Cata- 

 lina Island. California, in 4 to 15 fathoms. 



White, pale green, or straw color, quite tri.uonul and ])luinp. often 

 containing- the nepionic young. 



PSEPHIDIA OVALIS Dall, 1902. 



Pril)ilof Islands, Bering Sea, the eastern Aleutians, and the main 

 coast eastward and southward to San Diego, California, in H to 20 



fathoms. 



Yellowish white, oval, su])compressed, and attaining a largei- size 



than P. lordl. 



''nephU t,minyaUs'' Carpenter. 1S(U, is the nepionic young of 

 Petricola. as determined from the type specimens. The name has 

 often been mistakenly applied to P. ovalix, and the latter has also ])een 

 mistaken for P. lordi in the absence of figures or typically named 

 specimens. A species of P.^ephldhi quite near to P. ovalix occurs in 

 the Pleistocene terraces of Volcano Bay, Yesso. Japan, where speci- 

 mens were collected by Pumpelly. 



GEMMA GEMMA Totten, 1834. 



Shores of San Francisco Bay, introduced with '-seed" oysters from 

 Chesapeake Bay about 1SH9. 



The form obtained is the variety pnrpw^ea Lea. For synonymy, 

 etc., see Atlantic list. It is not yet certain that the species is estab- 

 lished on the Pacific coast. 

 NOTES ON AND DESCRIPTIONS OF WEST COAST AMERICAN SRECIES. 



The available material for the west coast of South America is so 

 meager that no attempt has been made to include species which do not 

 reach the southern limit of the Panamic fauna near Payta, Peru. 



CLEMENTIA SOLIDA, new species. 

 Plate XIV, fig. 4. 

 Shell large and solid for the genus, with an obscure ridge extending 

 from near the beaks to the posterior end of the basal margin; umbonal 

 reo-ion concentricallv undulnted and the whole shell conccMitrically, 

 somewhat irregularly, strongly striated; beaks prominent, small; unu- 

 lar region deeply hupressed, though there is no defined lunule or 

 escutcheon; ligament short, on strong nymphs; three entire cardinal 

 teeth in each valve; inner margins smooth; adductor scars large; pal- 

 lial sinus narrow, long, obliquely ascending, rather blunt in front. 

 Height, 63; length, 79; diameter, 34 mm. 



