Dr. P. P. Carpenter on new Forms of Mollusks. 45 
large, obtuse, conical protuberance, slightly curved upwards, 
that extends considerably beyond the spinners; it has a bright 
silvery lustre; a black band extends along the middle of the 
upper part to the posterior conical protuberance, and is crossed 
at its anterior extremity by a broad strongly curved black band, 
within whose curvature there is a short transverse line of the 
same hue; on each side of the medial band a shorter, nearly 
parallel black band occurs; these bands, which commence near 
the extremities of the curved band, are connected anteriorly by 
a transverse black bar, laterally by four oblique lines of the 
same hue, diverging in pairs from the medial band, and poste- 
riorly by converging till they meet ; irregular longitudinal bands 
and short oblique streaks on the sides, and a space round the 
spinners, have a black hue, the last comprising four silvery spots 
disposed symmetrically about the spinners; the sexual organs 
are moderately developed, and of a dark reddish-brown colour, 
that of the branchial opercula being yellowish brown. The 
cephalothorax is small, slightly convex, glossy, compressed be- 
fore, rounded in front and on the sides, with a large indentation 
in the medial line; the falces are short, powerful, very convex 
in front, rather divergent at the extremity, and armed with a 
dark, red-brown fang, and a few teeth on the inner surface ; the 
maxille are divergent, and increase in breadth from the base to 
the extremity, which is somewhat angular on the outer side ; 
the sternum is heart-shaped, with small prominences on the 
sides, opposite to the legs ; the legs are long, slender, and pre- 
vided with hairs and spines: those of the specimens from which 
the description was made were mutilated ; but, from the relative 
length of the femora, it is evident that the first pair is the 
longest, then the second, and that the third pair is much the 
shortest; the palpi are short and slender. These parts have a 
yellow-brown colour. The lip is semicircular and prominent at 
the apex, which has a yellow-brown hue, that of the base being 
dark brown. The eyes are nearly equal in size, and are seated 
on black spots on the anterior part of the cephalothorax ; the 
four intermediate ones form a square, and those of each lateral 
pair (which are placed on a minute tubercle near to each other, 
but not in contact) are rather the smallest of the eight. 
V.—Diagnoses of new Forms of Mollusks collected at Cape 
St. Lucas by Mr. J. Xantus. By Puiuip P, Carpenter, 
B.A., Ph.D. 
[Concluded from vol. xiii. p. 479. | 
37. Mangelia subdiaphana. 
M, testa parva, subdiaphana, albida, interdum rufo-fusco pallide 
