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VENUS TANTILLUS (PL XV. Fig. 10.) 



T. parva, ovato-trigona, ventricosa, inequilateralis, solidula ; levis vel sulculis 

 remotis concentricis arata, alba, postice fusco tincta ; margine dorsali antico 

 recto, angulo ventral! rotundato ; margine dorsali postico longiori, rectiusculo, 

 angulo acuto. 



Shell quite small, rather solid, ovate-trigonal, inequilateral ; beaks 

 acute, surface smooth or faintly waved with distant concentric fur- 

 rows ; the dorsal margins are nearly straight, and meet at the apex 

 in a right angle, but the posterior side is a fourth longer than the 

 anterior; the anterior basal angle is well rounded, while the poste- 

 rior is acute ; basal margin gently curved. Color white, but the 

 posterior third is stained deep slaty blue outside and in, the line of 

 demarcation being quite abrupt and well defined ; there is also a 

 pencil of the same color inside, running from the beak to the ante- 

 rior cicatrix ; the rest of the interior is cream colored. 



Length one fourth of an inch ; height one fifth of an inch. 



Inhabits Santa Barbara. Col. Jewett. 



This, little Venus reminds one of V. gemma, for its minute size, 

 but may more properly be regarded as a miniature of V. meretrlx 

 on account of its form and coloration. Its solidity, and the develop- 

 ment of its hinge, mark it as an adult shell. 



PURPURA PAXSA. 



PURPURA PATULA is noted as inhabiting the West Indies, the Medi- 

 terranean, the Philippine Islands, the west coast of America, &c. 

 Without being able to determine whether all these points are really 

 localities for the shell received under this name, I have compared 

 some of the specimens known to come from the west coast of Ame- 

 rica with some known to come from the Atlantic and Mediterra- 

 nean, and find the following differences. 



The Atlantic or Mediterranean shell is a large, solid, hemispher- 

 ical shell, with blunt, moderately developed tubercles externally ; 

 interior well coated with enamel, white with a chestnut blotch within, 

 and having the lip piceous, or dashed with that color ; the left lip 

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