266 DISCOVERY REPORTS 



Present knowledge indicates that the distribution of this species is in the Mediterranean and the 

 warmer waters of the Atlantic. In the Benguela current samples it occurred at Stations WS 975-8, 

 980, 986 and 996-8, with a much larger number of specimens in samples above 250 m. than below. 



O'lmm 



Fig. 2. C. teretivalvata n.sp. a, male from left side; b, anterior (left) unsymmetric gland of male from inside the shell; 

 c, posterior (right) unsymmetric gland and medial gland of male from inside the shell ; d, frontal organ of male ; e, frontal organ 

 of female;/, female from left side. (Figs, b, c, d from holotype ; a, e and/ from paratypes.) 



The species may be distinguished from other species of the genus, except C. rotundata Miiller, by 

 the form of the shell coupled with the position of the unsymmetric glands. As far as is known, it 

 differs from C. rotundata morphologically in its size, and in the form of the male frontal organ, as well 

 as in its distribution. 



