NO. 1312. SYNOPSIS OF THE VENERIDjI>-DALL. 397 



MARCIA RUFA Lamarck, 1818. 



Chile, northward to the Gulf of Panama. 



This is the Venus opaca of Sowerby, 1885, and has the external fea- 

 tures (but not the hinge) of /Saxidomv.s; there is also a oircuniscriljed 

 lunule. Venus lithotdd Jonas, 1844, is synonymous and T" e^cpullexcenH 

 Philippi, 1844, is based on the 3'oung shell. The striation on the ante- 

 rior half of the shell varies and may be obsolete. On a smooth spec- 

 imen Deshayes, in 1853, founded liis Saxldoimis sfjiudidus, a name 

 which has been wrongly applied to a northwest coast species. Jonas 

 stated in his diagnosis that there is no lunule, Imt his own drawing, 

 given by Philippi, shows it to l)e present; and in separating Philippi's 

 figure from Jonas's name Deshayes overlooked the fact that both were 

 deriv^ed from Jonas himself. He also duplicates the species bj^ enter- 

 ing it as Chione ritfa in his list. 



MARCIA (VENERELLA) SUBDIAPHANA Carpenter, 1865. 



Unimak Pass, Alaska, east and south to the Santa Barbara Channel, 

 in 10 to 120 fathoms. 



Thin, white with olive gray periostracum; variable in form from 

 trigonal to long ovate. Described by Carpenter under the name of 

 dementia . It reaches a length of 63 mm. and is found in the Pliocene 

 of California. 



PAPHIA (PROTOTHACA) GRATA Say, 1831. 



From Turtle Bay, on the Pacific shore of Lower California, to Cape 

 !St. Lucas, the Gulf of California, and southward to Panama Bay. 



This beautiful species revels in color variations, many of which have 

 received names. Thus it is the Venus discors^ tricolor, fuseol/neata^ 

 and JuKtrioniea of Sowerl)y in 1835, and was called straminea (as of 

 Conrad) by him in 1852. Deshayes referred it to Chione and described 

 a Tapes grata from the Philippines in 1853, which is a wholly different 

 shell, named T. deshayesii by Carpenter in 1864. It was called Venus 

 m/uscaria hy Reeve in 1863, but it is not the Oytherea muscaria of 

 Lamarck in 1818. V. pectun cut aides Valenciennes, 1846, ma}' be 

 synonj'mous. The escutcheon varies from distinct to obsolete, and 

 the species can not be divided on this character. Tapes iJuetuosa 

 Sowerby, 1853 not of Gould. 1841, is prol)ably a young shell of this 

 species. 



PAPHIA (PROTOTHACA STAMINEA Conrad, 1837. 



North Japan, Sakhalin, Kamchatka. Bering Island, the Aleutians, 

 and the west coast of America, from the peninsula of Alaska south- 

 ward to Cape St. Lucas and Socorro Island. 



I have seen no specimens of this species from the Pribilof Islands 

 or from south of Socorro Island. The specimens from Panama 



