CYCLOSTREMA. 



§7 



C. NiTENs, Phil. PI. 88, fig. 97. 



Narrowly umbilicated, more depressed and thicker, more glossy 

 than the preceding species; there are a few indistinct grooves on the 

 upper part of the umbilicus, otherwise the surface is smooth and 

 polished. Diam. 87 mill. Euroj)e. 



Margarita pusilla, Jeffreys is a synonym. 



Var. Alderi, JefiTreys. 



Shell thinner and more transparent. Skenea Icevis, Forbes and 

 Hanley is possibly identical. 



C. TROCHOiDES, Jeffi'eys. PL 33, figs. 98, 99. 



Perforate, somewhat solid, white, opaque, smooth, shining, base 

 sometimes with a few faint oblique, curved lines; whorls 4, convex, 

 with deep suture; columellar lip vertical, forming a slight angle 

 with the outer lip at their junction. Diam. 2 mill. 



• Norway. 



It is C. Peterseni, Friele. 



C. Dalli, Verrill. PL 33, fig. 100. 



Umbilicus imperforate or narrowly rimate, yellowish white, smooth 

 except for minute grooth-lines; whorls 3 i, rapidly enlarging, well 

 rounded, with deep suture, base with seven or eight spiral incised 

 lines. Diam. 2*25 mill. 



Off N. England Coast. 



It is C. troehoides, Verrill, not Jeffreys. 



Var. ORNATUM, Verrill. PL 33, fig. 1. 



Spiral lines of the base crossed by thin, impressed, oblique lines. 



C. BiTHYNOiDES, Jeffi'eys. PL 33, fig. 23. 



Narrowly umbilicated, thin, the fine growth lines crossed by 

 microscopic close-set spiral strife, giving the surface a frosted appear- 

 ance, whitish; whorls 3?, rapidly increasing, the last tumid; peri- 

 stome continuous, but partly adnate. Diam. 1"25, alt. 1'66 mill. 



European Atlantic (Porcupine Exped.), Mediterranean. 



C. AFFiNis, Jeffreys. PL 33, fig. 5. 



Narrowly umbilicated, rather thin, semitransparent glossy, with- 

 out sculpture, white, suture narrow but deep; whorls 4, swollen, 

 rapidly increasing; periphery simple, acute. Diam. 1'87 mill. 



Bay of Biscay, Palermo; 103-913 /)us. 



