MUSEUM OF COMPARATIVE ZOOLOGY. 41 



Station 12, 177 fms. ; Barbados, 100 fms. ; Station 20, 220 fms. 



This little shell has much the form of Trochus transenna W. The regular- 

 ity of its asperities has a very pleasing effect, and it seems <piite different from 

 any described species. 



Margarita scabriuscula n. s. 



Shell white, conical, compact, very thin, with a silky lustre ; whorls, five to 

 six, suture not channelled ; nucleus bulbous, polished, smooth ; next whorl 

 and a half having a sculpture of slightly raised ribs like a minute Scalariaj 

 on the following whorls the upper surface decorated with two carinae, sculp- 

 tured with closely set, angular, buttressed projections, like those figured by 

 Watson on the carina; of Trochus clavatus (PI. V. fig. 8), but the buttresses are 

 not continuous over the whorl, so as to form transverse ribs, and the second 

 carina is within the periphery of the last whorl, which is bordered by a sharp, 

 angular carina, without nodules or projections ; two similar, but lightly nodu- 

 lated, intervene on the somewhat rounded base between the last and the nodu- 

 lated boundary of the umbilical chink, which is nearly filled by the reflected 

 pillar ; the lines of growth radiate in a wavy manner from the umbilicus over 

 the whorl, and constitute the remaining sculpture ; there are no longitudinal 

 stria; of any kind, or any ribs except those described ; the aperture is nearly 

 rectangular, a little wider than high ; the sides of the spire are rather a little 

 inflated than simply conical. Alt. 4.75. Lat. of base, 4.0. Lat. of aperture, 

 1.62; alt. 1.12 mm. 



Station 44, 539 fms. 



This has the characteristic aspect of an abyssal shell. 



•Margarita lissocona n. s. 



This species belongs to the same group as the last three mentioned species, 

 but is nearest to the last. The shell is more simply conical, consisting of six 

 and a half whorls, which glisten with that peculiar spun-glass or flossy lustre 

 noticeable in so many abyssal species ; the nuclear whorls as in the last; then 

 the sculpture consists of two lines closely appressed to the sutures, less promi- 

 nent and less conspicuously provided with the angular projections than in the 

 last species. Between the upper and lower lines the surface of the whorl is 

 smooth, except for lines of growth, shining as above described, and Beems even 

 a little concave. The nodules on the upper carina of one whorl tit into the 

 spaces between the nodules on the lower carina of the preceding whorl, and 

 thus alternate, along the line of the suture and give it a wavy character. The 

 carina on the last whorl is seen to lie formed by two threads, which constitute 

 the periphery, with fainter angularities than the others. The base is somewhat 

 inflated, with two sharp, smooth threads between the periphery and the nodu- 

 late boundary of the small funnel-shaped umbilicus. The lines of growth are 

 much as in the last species, the umbilicus is nut infringed upon by any lvtlcc- 



