188 A. E. Verrill — Molhisca oj the Nein England Coast. 



Odontophore very small and slender; median tooth minute, thiu, 

 with the tip bent forward and ending in a minute central denticle; 

 inner laterals, with the tip small, curved forward, flat, unarmed, 

 almost half as wide as the median ; outer laterals long, slender, 

 very acute, strongly curved. 



Length of the largest specimen, 5""" ; breadth, 4™"" ; breadth of 

 aperture, 2"™. 



At station 2084, two younger specimens were obtained. These, 

 while agreeing with the larger specimens in form and sculpture, 

 have a narrow but deep umbilical peiforation, which is only partially 

 concealed by the reflexed columella-margin. One specimen has five, 

 the other six spiral carinae on the base. The columella-margin is 

 thin and shows only a small tooth at its extremity. The nucleus, as 

 in the typical form, is small, smooth, turned up oblitjuely, and some- 

 what prominent. The presence of the umbilical perforation seems to 

 be due only to immaturity. 



Seguenzia formosa, var. nitida Yerriii, nov. 



This shell agrees nearly in form and size with typical S. formosa, 

 but is thinner, more translucent, with the spire a little less acute, 

 and with more delicate sculpture. It differs chiefly in having more 

 numerous and closer spiral lines on the base, the number below the 

 median carina of the whorl being ten to twelve, the intervals be- 

 tween them diminishing as they approach the umbilical region. 

 Our specimens have a narrow, spirally twisted, deep umbilical perfo- 

 ration and channel, mostly concealed in a front view by the reflexed 

 edge of the columella-lip ; the umbilical pore is bordered externally 

 by the innermost spiral ridge. The columella is much excurved at 

 base, strongly spirally twisted, and projects at the end in a some- 

 what prominent, excurved angle, forming a small canal, but has no 

 distinct tooth on the inner margin like that seen in the typical S. 

 formosa, but this may be due to injury; the outer lip is more regu- 

 larly convex and has a less developed posterior sinus. The two 

 principal carina^ on the whorls are elevated and rather prominent, 

 with the edge a little thickened, often obtuse and finely spirally 

 lined, not interrupted by the transverse riblets, which fade out at a 

 little distance below the crest, except on the sutural carina, which 

 they cross. The riblets are rather thinner, more delicate, and more 

 numerous than in the typical S. formosa, and are less elevated. 

 They- are also more strongly curved and decidedly closer together, 

 especially those between the two peripheral carina\ There is, also, 



