CERION, GROUP II. 183 



gubernatorium 

 martensi elans album 



cyclostomum maritimum pannosum 



scalarinum mumia 



regina. 



II. Group of C. pannosum. 



Longidens MAYNARD, Contrib. to Sci. iii, p. 39, type S. pannosa. 

 All of the forms known from Little Cayman and Cayman Brae, 

 islets which lie south of Cuba, have the parietal tooth elongated, its 

 length about four times the height of the tooth. They are not especi- 

 ally related to long- toothed species of the Bahamas. The species 

 have been absurdly over-divided. 



a. Shell very small arid slender (diam. 5-6 mill.), the whorls im- 

 pressed below the suture. nanus, p. 183. 

 a 1 . Shell larger, much stouter. 



b. Conical part of the spire ribbed, rather short. 



pannosum, p. 184. 



b l . Only one or two whorls of the cone, following the smooth 

 apical whorl, ribbed (cylindric portion ribbed or 

 smooth); the conical portion longer, more slowly taper- 

 ing and acute, mainly smooth. levigatum, p. 189. 



. NANUS (Maynard). PI. 27, figs. 1, 2, 3. 



Shell small, cylindric or tapering, rather thin, dirty white, flesh- 

 tinted at the apex and where worn. Whorls 8^-10^, the earlier 2-J- 

 corneous or fleshy, nearly smooth, those following ribbed, the ribs 

 rather narrow, 19-23 in number on the penult whorl. The later 3 

 or 4 whorls are constricted below the sutures, then convex. Umbil- 

 ical chink short. Aperture ovate or rounded-ovate, brownish inside ; 

 lip flatly but narrowly reflexed, thickened within ; parietal callus 

 strong. Parietal lamella rather strong, fully one-third of a whorl 

 long. Axial lamella, very weak, hardly noticeable from the aperture. 



Length 17, diam. 5, length of aperture 4.8 mill. 



Length 15.5, diam. 6, length of aperture 5.7 mill, (typical). 



Length 13, diam. 5, length of aperture, 4.8 mill. 



Little Cayman Island. 



Strophia nana MAYN., Contrib. to Sci. i, p. 27, pi. 2, f. 11, a, 6, c. 

 O889). Cerion nanum PILS. & VAN., P. A. N. S. 1896, p. 318. 



