744 rnui'. o. v. saus ox [May 3, 



shape. EjiUMilr.tory tubi's (liif. 18) e.-u-li with oigiit vertii-iis of 

 cliitinoiis stripes, extremities of tube not dilateil. 



Length of shell 2 *J"47 mm., height 0"23 mm., widtli Oil) mm. 



Remarks. — 'I'iiis form is evidently nen.j-ly allied to tlie preceding 

 one, but is of smaller size and difl'ers conspicuously in the shape 

 of the shell, which, moreover, does not e.\hi))it tlie characteiistic 

 obliquity found in that species. 



Occurrence. — Some few specimens of this foi-m were found in 

 the same sample (138) in which the pi-eceding species occurred, 

 and solitary specimens were found in two other san)ples from 

 Tanganyika, the one (169) taken 18/11/04 at Kala (E. shore of 

 lake), the other (240) 24/2/05 at Baraka (N.W. shore). 



15. Cypiuuopsis cuxxiXGToxi, sp. n. (Plate LXX. figs. 1-3.) 



Specific Characters. — Female. Slioll rather compressed ; seen 

 laterally (tig. 1) of a somewhat trigonal foi'm, greatest height 

 occurring a little in front of the middle and considerably ex- 

 ceeding half the length, anterior extremity i-ounded, jjosterior 

 much narrower and terminating below in an obtuse corner, 

 dorsiil margin strongly arclied in the middle, ventral one slightly 

 sinuated ; seen dorsally (fig. 2) narrow oblong in form, greatest 

 width about equalling one-third of the length and occurring in 

 the middle, both extremities acuminate. Yalves rather thin an<l 

 nearly equal, finely hairy at both extremities. Surface of shell 

 smooth. 



Male (fig. 3) of somewhat larger size than female, and having 

 the shell more deeply sinuateil ventrally, with the posterior 

 extremity narrower and more deflexed. 



Length of shell ? 0-56 mm., height 0-32 mm., width 0-20 mm. 



Remarks. — This is a quite genuine C'l/pridopsis, i'esend)ling 

 somewhat in .shape the type species, C. r'dlosa J urine, but having 

 the shell less densely pilose and the valves much less unequal, 

 without any obvious obliquity of the shell. It is the largest of 

 the species here recorded. 



Occurrence.— Tvfo specimens only of this form, a female and a 

 male, have come under my notice. They were derived from a 

 sjimple (14) taken 17/6/04 in Monkey liay, Lake Nyajsa, and had 

 l)een separated by Dr. Cunnington in a small tube. I therefore 

 find it ap[)ropriate to name this species in honour of the dis- 

 tinguished conductor of the Expedition. 



16. CYriiiDorsis itsilla, sp. n. (Plate LXX. figs. 4-6.) 



Specific Characters. — Female. Shell modeiately com])re.ssed ; 

 seen laterally (fig. 4) oval in form, greatest height occurring a 

 little behind the middle and equalling about h;df the length, both 

 extremities obtusely rounded and slightly ileHexed, nearly equal, 

 dorsal margin .somewhat irregularly curved, ventral almost 

 straight; seen doisally (fig. 5) oblong in form, greate.st width 

 about ecpialling two-fifths of the length and occurring in the 

 middle, both extremities somewhat blunted at the end. Valves 



