30 
DESCRIPTION OF CERASTUS DINSHAWT, n.sv., FROM ADEN, 
WITH A NOTE ON OTOPOMA CLAUSUM, Ssy., AND 
O. YEMENICUM, Bret. 
By E. R. Syxes, B.A., F.L.S., ete. 
Read 3rd April, 1908. 
Cerastus DinsHawl, n.sp. 
Shell acuminately pyramidal, with a well-excavated area in the 
umbilical region, protoconch flattened above ; whorls 83, plano-conyex ; 
the sculpture consists of longitudinal striation, fine on the earlier whorls, 
but suddenly becoming much stronger and coarser, both on the last 
two-thirds of the last whorl and in the umbilical area; further, fine 
(almost microscopic) spiral lines, densely set together, encircle the 
shell. The colour is very pale yellow to white, and the majority 
of the specimens are stained with chestnut inside the mouth and 
on the last whorl; the mouth is somewhat drawn to the side, with 
a large ‘flaring’ lip, thickened internally and widely expanded, the 
edges becoming thin and generally being broken; a light callus joins 
the inner and outer margins; the columella is marked by a strong, 
spirally ascending fold. Dimensions: height of shell, 36 mm. ; 
width of last whorl at the back (without the lip) 15 mm. ; height 
of mouth (including the lip) 21mm.; width of mouth (including 
the hp) 18 mm. 
Cerastus Dinshawi, v.sp. 
HTab.—Senna, about 100 miles from Aden. 
Type in the British Museum, presented by Comm. E. R. Shopland. 
This species belongs to the group of C. Deflerst, Jouss., and 
C. Adanicus, Jouss.,! neither of which has been figured, so far as 
T can trace, and of which I find no mention in Dr. Kobelt’s monograph.? 
For other kindred species see the papers by Bourguignat * and Martens.‘ 
1 Bull. Soc. Malac. France, vol. vi (1889), p. 345. 
2 Buliminide, in ‘‘ Conch.-Cab.,’’ 1899-1902. 
> In Réyoil: ‘* Faune et Flore des pays Comalis.”’ 
4 Nachrbl. Deutsch. Malak. Ges., 1889, p. 145. 
