MAZATLAN BIVALVES 41 



Rathke, Siemasclike. — Santa Barbara, abundant, Nuttall.— 



Mazatlan : not common ; L'pool Col, 



Tablet 129 contains 6 pairs and 2 valves, shewing variations. 

 The smaller valve may be T. cicercula, Fhil., in Zeitschr.fur 

 Mai. Feb. 1846, p. 19. I cannot however separate it from 

 S. carnaria, of which it appears the young. The description of 

 T. cicercula exactly applies to this, which is the left valve. 

 Menke in quotiag the species among Melchers' Mazatlan Shells, 

 Zeitschr.f. Mai. 1847, p. 188, no. 53, says that it is only the left 

 valve which possesses the sculpture in question : so does the left 

 valve of T. carnaria, and that alone. Menke loc. cit. describes a 

 new species, T. areolata, from the West Indies, intermediate 

 between T. cicercula and T. carnaria, with a similar smooth 

 space on the left valve. — Philippi also describes from Mazatlan 

 (loc. cit.) T. lenticula, T. dichotoma, and T. ervilia. In his 

 Abbd. Conch, for Aug. 1846, p. 24, he also gives the ancient 

 T. pisiformis. Linn, (along with Diplodonta semiaspera) as 

 common to Mazatlan and the Caribbsean Sea. Mazatlan must 

 be rich in Strigdlse, according to Phdippi ! 



67. PSteigilla lenticula, Phil. 



Tellma lenticula, Phil, in Zeitsch.f. Mai. 1846, p. 19. 



Tablet 130 contains a broken specimen which probably be- 

 longs to this species, which, says Phdippi, while agreeing in 

 form and size with T. pisiformis, has the sculpture of Lucina 

 digitaria. It may however belong to Lucina eburiiea, Rve. 

 Conch. Icon. pi. 8, f. 49, found in sandy mud, 11 fm., St. Elena 

 and Panama, Cuming. 



Hah. — Mazatlan, Philippi. — ?Do. fragments, off the back of 

 Chama ; L'j^ool Col. 



68. , sp. ind. 



Tablet 131 contains a fragment of a thin shell of moderate 

 size, perhaps a Psammobia, (possibly an unknown Donax,) 

 strongly angulated, with very fine, slightly rugose stria;, 

 coarser on the angular part. It is white, slightly bordered 

 with orange. 



Hab. — Mazatlan ; confined in the mouth of Trivia sanguiuea ; 

 L'pool Col. 



