38 CRYPTOPHTHALMUS. 



length of the animal, depressed, subcordate, triangular, convexly 

 truncate in front, posteriorly separated by a fissure into two lobes, 

 eyes deeply immersed in the cephalic disk, inconspicuous from 

 above, their position being indicated by small pale spots, they can 

 be distinctly seen by turning up the sides of the disk. The lateral 

 lobes closely envelope the body, extending from the head to the ex- 

 cretory tube, the left one overlapping the right ; excretory tube at 

 the posterior end of the body, short convolute. There is no groove 

 between the lateral lobes and the locomotive disk. Color dusky 

 olive, margins of the cephalic disk paler than centrally, and foot 

 paler than above. When disturbed, the animal contracts itself as- 

 suming a spherical form. Its motions are languid. Station on sea- 

 weed in shallow water. (Pse.). 



Tahiti, on seaweed. 



Crypt, cylindricm PSE., P. Z. S. 1861, p. 245; Amer. Journ. 

 Conch, iv, p. 74, pi. 7, fig. 7. 



Section PHANEROPHTHALMUS Adams, 1850. 



Phanerophthalmus A. AD., Thes. Conch, ii, pp. 559, 599. Xan- 

 thonella GRAY, Figs. Moll. Anim. iv, p. 95 (1850). 



Shell small, white, wholly buried in the mantle ; entirely open, 

 the spire indicated by an incurved hook on the middle of the left 

 margin ; lip prolonged in a point above. 



Animal large, elongated, with foot as long as the body. Cephalic 

 disk short, bearing distinct sessile eyes, bilobed behind ; parapodial 

 processes large, reflexed and meeting over the back. Male orifice 

 anterior, female posterior. 



The parapodial lobes are rather smaller than in Cryptophthalmus > 

 and the eyes more posterior. 



C. LUTEUS Quoy & Gaimard. PL 2, figs. 27, 28, 29, 30. 



Shell small, fragile, white, oval, open, not spiral ; right margin 

 sinuous and acute. 



Body much elongated, rounded ; head shield emarginate in front, 

 rounded at the sides, with two short posterior lobes ; foot widened 

 in front, then constricted, rounded behind ; parapodial lobes long, 

 curved over the back where they meet in a sinuous groove and a 

 small hiatus behind. Eyes small, black, widely separated. Gill 

 posterior, to the right, not visible externally. A groove joining 

 the genital openings is on the same side. Shell contained within 



