MUSEUM OF COMPARATIVE ZOOLOGY. 355 



An examination of the soft parts showed the operculum to be very thin, 

 liirht brown, and with about seven whorls. The animal was of a whitish color 

 without any spots or markings, and with very large black eyes set on a good- 

 sized peduncle closely adjacent to and behind the tentacles. There is a single 

 narrow gill in the usual position. The tentacles are long, large, and rather 

 slender; the foot short, broad, and bluntly rounded in front, behind almost 

 truncate, in fact the contracted specimen looked almost as if there was a broad 

 posterior indentation in the middle line. The muzzle is long, narrow, sub- 

 cylindrical above and transversely expanded at its distal end, which is semi- 

 lunar with a densely papillose surface and fringed edges. This expansion is 

 nearly three times as wide as the stem of the muzzle. Epipodium with a large 

 lobe behind the eye peduncle but not connected with it; behind the lobe is 

 one long process and then a shorter one. The frill behind is merely puckered, 

 but from under the borders of the operculum on each side protrude three good- 

 sized processes. Behind the opercular lobe the epipodium terminates in a 

 prominent point, concave and papillose on its upper surface. There are no 

 frontal lobes between the tentacula. The epipodial point extends some dis- 

 tance behind the posterior end of the foot. The jaw is like that of Calliostoma 

 in shape, composed of brown four-sided translucent prismatic rodlets which 

 give under the microscope a reticular marking of diamond-shaped spots to the 

 surface of the jaw; the two sides are not united in the middle line. The 

 dentition closely resembles that of Lunella versicolor Gmelin as figured hj 

 Troschel (Geb. der Schnecken, II. pi. xx. fig. 1), except that the bases of the 

 rhachidian and lateral teeth are subcircular, and on a few of the scythe-shaped 

 cusps of the numerous uncini are a few denticles. There are five lateral teeth, 

 and between twenty and thirty uncini. 



The nucleus in this species is often caducous, and in such specimens the 

 apex is pierced with a circular perforation a millimeter and a half in diameter, 

 which is continuous with the umbilicus. There does not appear to be any 

 particular difference in appearance between the nucleus and the early whorls, 

 its loss would therefore seem to be due merely to its fragility. In none of 

 those in which it remains is there any indication of its being reinforced by a 

 shelly deposit. 



Gaza Fischeri n. s. 



Plate XXXVII. Fig. 6. 



This shell is of six and a half whorls, and closely resembles Gaza dccdala 

 Watson, except in the following particulars. It is much more depressed pro- 

 portionally ; the upper margin of the aperture is distinctly depressed below its 

 general plane; and the radiating lines, almost microscopic in G. clmlala, are in 

 this form impressed in the early whorls near the suture, so as to produce a 

 succession of short ripples, following the recurved lines of growth, which 

 give a fringe-like ornamentation to the suture, at the rate of about five 

 ripples to a millimeter. Nothing like this is visible in any of the specimens 



