On Megalocypris princeps. 



in all essential characters, though evidently specifically dis- 

 tinct, exhibiting well marked differences in the form of the 

 shell and its degree of hairiness. I restrict myself in the 

 present paper to a description of the one species. 



Megalocypris princeps, G O. Sars, n. sp. 



(See accompanying plate.) 



Specific Characters — Shell, seen laterally, oblong* 

 reniform, more than twice as long as it is high, dorsal 

 margin perfectly straight and horizontal, slightly angular in 

 front, ventral margin distinctly sinuated in the middle, an- 

 terior extremity broadly rounded, posterior slightly deflexed 

 in female, more obtuse in male, — seen dorsally, oval fusi- 

 form, greatest width, not attaining the height, in the middle, 

 side-contours evenly curved, both extremities narrowly pro- 

 duced. Valves thin, smooth, very minutely hairy in front 

 and behind. Caudal rami very slender, slightly flexuous, ta- 

 pering distally, hind edge minutely spinulose, distal claw 

 about V 3 as l° n g as the ramus, apical seta nearly half as long 

 as the distal claw Colour in preserved specimens light yel- 

 lowish green, with scattered darker green shadows. Length 

 of female 7.30 mm. of male from 6 1 /? to 7 mm. 



Remark s.— In the anatomical details this form almost 

 exactly agrees with the second South African species, for which 

 I propose the name of M. Hodgsoni ; but the shell exhibits 

 well-marked differences in both sexes. In the present species 

 it is narrower and less tumid, and the posterior extrem- 

 ity is less deflexed, especially in the male. The valves are 

 also less hairy than in M. Hodgsoni. 



Description. — The shell of the largest female 



