1910.] OSTRACODA FROM TANGAXVIKA. 735 



than half as large as P. complunata. The specimen examined is, 

 however, evidently fully grown, as proved by the well-developecl 

 ejaculatory tubes shining through the pellucid shell. The shape 

 of the latter conspicuously differs from that of either of the two 

 preceding species. 



Occurrence. — A solitary male specimen of this form wiis found 

 in a sample from Tanganyika (138), taken 13/10/04 at Sumbu 

 (S.W. of lake). 



4. Paracyprta obtusa, sp. n. (Plate LXV.) 



Hpecific Characters. — Female. Shell moderately compressed ; 

 seen laterally (fig. 1) of oval or elliptical shape, greatest height 

 occurring about in the middle and slightly exceeding half the 

 length, both extremities obtusely rounded and nearly equal, 

 dorsal mai^gin gently curved with trace of an angle behind the 

 ocular region, ventral margin very slightly concaved in the 

 middle; seen dorsally (fig. 2) oblong in shape, greatest width 

 somewhat exceeding one-third of the length and occui'ring a little 

 behind the middle, anterior extremity narrower and more 

 acuminate than the posterior. Valves rather thin and pellucid, 

 conspicuously unequal, the right one being overlapped by the 

 left along the whole anterior extremity, as also a little behind ; 

 anterior lips of both valves bordered by a very thin and pellucid 

 rim. Surface of shell exhibiting a very fine longitudinal stria- 

 tion, only visible under high magnifying-powers (fig. 4), and 

 clothed at each extremity with extremely delicate hairs. Inner 

 coating of valves exhibiting a somewhat irregular reticula- 

 tion, more conspicuous at the anterior extremity (fig. 1). Limbs 

 (figs. 5-11) on the whole somewhat more strongly built 

 than in the type species, but otherwise identical in structure. 

 Caudal rami (fig. 12) slightly curved, with the claws moderately 

 strong and less unequal than in P. d-eclivis, the distal one about 

 equalling half the length of the ramus ; dorsal seta well developed 

 and rather slender. 



Male (fig. 3) of about same size as female, and having the 

 shell very similar in shape. Sexual characters, manifested in 

 the strvicture of the inferior antenna (fig. 13), the palps of the 

 posterior maxillte (figs. 14, 15), the copulatory appendages (fig. 16), 

 and the ejaculatory tubes (fig. 17), agreeing exactly with those in 

 other species of this genus. 



Length of shell 0'63 mm., height 0*33 mm., width 0-22 mm. 



Remarks. — In the general shape and sculpture of the shell, 

 this form exhibits a certain I'esemblance to the species of the genus 

 Cypria Zenckei-, and, indeed, at fii-st I was inclined to regard it 

 as a member of that genus. On a closei' comparison and exami- 

 nation of the several appendages, I find it, howevei', impossible 

 to separate this form generically fi-om the other sj^ecies here 

 recorded as belonging to the genus Paracypria. 



Occurrence. — This species seems to be by far the commonest 

 of the Ostracoda of the Tanganj'ika Expedition. I ha^e noted it 



48* 



