REPORT ON THE OSTRACODA. 69 



Cytherejinmarchica, Sars, and might perhaps, without much impropriety, be considered 

 as a variety of the former species ; the dorsal outline, however, is in Cythere luhbockiana 

 much more angular, the sides being almost rectilinear, and I have not observed any 

 trace of the tubercle which is so marked a characteristic of Cythere oblonga, as well as 

 of Cytherejinmarchica. Cythere oblonga is also a considerably larger species, having a 

 length of 1-2 9th of an inch. 



[PL XIV. fig. 6, a-d. a Shell seen from left side, b from above, c from below, d from 

 front. Magnified 50 diameters.] 



13. Cythere exilis, n. sp. (PL XVI. fig. 5, a-h). 



Shell of the female, seen from the side, oblong, subquadrangular, greatest height 

 situated near the anterior extremity, and equal to half the length ; anterior margin 

 boldly rounded, sometimes fringed below the middle with a series of minute teeth, 

 posterior much produced, narrowly rounded ; dorsal margin almost straight, ending in 

 an obtuse angle behind, ventral deeply and very abruptly sinuated in the middle, slightly 

 notched behind the middle, then gently curving upwards at the hinder end : seen from 

 above, compressed, subovate, width considerably less than half the length, extremities 

 nearly equal, obtusely rounded, sides subparallel, and slightly sinuated in the middle, 

 converging very gradually towards the extremities ; end view irregular, slightly higher 

 than broad, ventral margin broad, convex and emarginate in the middle, dorsal strongly 

 arched. The surface of the valves is undulated, marked with irregular longitudinal 

 ribs, and Avith numerous large angular excavations, the margins of the valves forming, 

 especially at the two extremities, a stout encircling fillet. The shell of the male (figures 

 e-h) is exactly similar, except in being narrower and more elongated. Length, l-34th 

 of an inch ('75 mm.). 



The only di'edging in which Cythere exilis was detected is from Simon's Bay, South 

 Africa. Depth, 15 to 20 fathoms. (Station 140.) 



[PL XVI. fig. 5, a-h. a Shell of female seen from left side, b from above, c from 

 below, d from front ; figures e-h refer to similar views of the male shell. All magnified 

 50 diameters.] 



14. Cythere murrayana, n. sp. (PL XVI. fig. 4, a-h). 



Carapace of the female, as seen from the side, oblong, subquadrangular, scarcely 

 higher in front than behind, height equal to half the length, anterior extremity rounded, 

 posterior narrower, subtnmcated and rather angular, the lower angle rounded ofi" ; dorsal 

 margin nearly straight, but, towards the hinder end, suddenly depressed and excavated, 

 ventral margin sinuated in the middle, and turned upwards behind ; seen from above, 

 the outline is subovate, width nearly equal to the height, sides slightly curved and nearly 

 parallel, extremities obtusely rounded ; end view subhexagonal, with olitusely-rounded 



