406 Gould's Descriptions of Shells 
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 ventrali 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. meretriz 
on account of its form and coloration. Its solidity, and the develop- 
ment of its hinge, mark it as an adult shell. 
PURPURA PANSA. 
PURPURA PATULA is noted as inhabiting the West Indies, the Medi- 
terranean, the Philippine Islands, the west coast of America, &e. 
Without being able to determine whether all these points are really 
loealities 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 3 
interior well coated with enamel, white with a chestnut blotch within, 
and having the lip piceous, or dashed with that color; the left lip 
