1910.] OSTKACODA FROM TAXOAXVIKA. 753 



and somewliat miequal, tlio distal one l)oiii,<i- iiuicli tlie longer and 

 considerably exceeding half the length of the ranins; ^eta of 

 dorsal edge well (le\'el()ped. 



Length of shell 0"94 nnn., height 0*50 nun., width across the 

 posterior protuberances 0"4() mm. 



Bemarks. — This form somewhat resembles the northei-n species 

 /. gihba Ramdohr, exhibiting a rather similar shape of the 

 shell, which, as in that species, is produced on each side behind 

 the middle to a well-marked protuberance; but these protuber- 

 ances ai'e in the present species considerably broader and more 

 obtuse at the tip, moi-e resembling those in the Chinese species 

 7. angulata G. 0. Sars. The structuie of the caudal rami is also 

 somewhat different. 



Occurrence. — A solitMry female specimen of this foi'ui w;is 

 found in a snmple from Lake Nya.sa (8), taken 11 (> 04 in 

 Anchorage Bay (B. end of lake). 



28. Ilyocypkis alta, sp. n. (Plate LXXIII. figs. 5-7.) 



Speci£c Characters. — Male. Shell less compressed than in the 

 preceding species, seen laterally (fig. 5) of a somewhat clavate shape, 

 greatest height occurring far in front and exceeding thi-ee-fifths 

 of the length, anterior extremity very broad and amply rounded, 

 ])osterior much narrower and blunted at the end ; doi'sal margin 

 forming in the ocular region an abriq^t angulai' bend and sloping 

 thence rathei- steeply behind, joining the posterior margin at 

 an obtuse angle, ventral mai-gin deeply sinuated in the middle : 

 seen doi'sally (fig. 6) of irregular oblong-ovate form, exhibiting, 

 as in the preceding species, on each side in front of the middle a. 

 rounded tuberculiform prominence, and farther behind a broad 

 obtuse protuberance, below which another somewhat smaller 

 protuberance occurs. Valves rather thin and pellucid, con- 

 spicuously unequal, the right one overlapping the left in front by 

 a rather broad hyaline rim, as also somewhat behind. Sin-face of 

 shell less distinctly dotted and clothed with scattered delicate 

 hairs. Caudal rami (fig. 7) comparatively shorter and .stouter 

 than in the preceding species and le.ss curved, apical claws nearly 

 equal in length, dorsal seta comparatively small. 



Length of shell 0'80 mm., height 0"51 mm., width across the 

 posterior pi'otuberances 0*40 mm. 



Reviarhs. — This form is iniquestionably specifically distinct 

 from the pi'eceding one, differing ratlier con.spicuou.sly both from 

 this and the other known species in the shape of the shell, as also 

 in the .structure of the caudal rami. 



Occurrence. — Of this form also only a solitary specimen has 

 come under my notice. It had been separated by Dr. Cunnington 

 in a small tube, and proved, on a closer examination, to be a 

 nearly adult male. According to the label it was found in a 

 sample from Tanganyika (169) taken 18/11/04 at Kala (E. shore 

 of lake). 



