REPORT OiSr THE OSTRACODA. 83 



Dredged ofi" Prince Edward's Island, 50 to 150 fathoms, near Station 145. 



[PI. XV. fig. 1 , a-c. a Left valve of male seen from side, h from above, c right valve 

 of male from side, d the same from above, e right valve of female seen from side. All 

 magnified 50 diameters.] 



37. Cythere rastromarginata, n. sp. (PI. XVI. fig. 1, a-cl and fig. 2, a-d). 



Shell compressed, oblong ; seen from the side, quadrangular, a little higher in front 

 than behind, greatest height situated over the anterior hinge, and equal to half the 

 length ; anterior extremity boldly rounded and fringed throughout with a series of 

 short, blunt, and subequal teeth ; jDosterior truncated, rounded, and produced at the 

 ventral angle, where it is armed with a row of six or eight strong, spine-like teeth ; dorsal 

 margin sloping with a sinuous curve backwards, and ending in an obtuse angle both 

 before and behind, ventral nearly straight ; seen from above, the outline is much com- 

 pressed, thrice as long as broad, with nearly parallel sides, and broadly truncated equal 

 extremities, the sides converging only very slightly towards the ends ; end view irregu- 

 larly ovate, height much greater than the width. Surface of the shell sculptured with 

 polygonal fossae, arranged in a somewhat radiate manner round a subcentral circular 

 tubercle ; the ventral surface forms two flattened, but only slightly extended lateral alse, 

 which are marked with very large excavated fossae. Length, 1-3 7th of an inch ('8 mm.). 



Males (fig. 1), dredged off reefs, Honolulu, 40 fathoms ; ofi" East Moncoeur Island, 

 Bass Straits, in 38 to 40 fathoms (Station 162). Females (fig. 2), in lat. 39° 32' S., 

 long. 171° 48' E., 150 fathoms (Station 167). 



The form figured in PL XVI. fig. 2, a-d, which I at first thought to belong to a 

 distinct species, I now believe to be, in all probability, only the female of that shown in 

 fig. 1, a-d. The general characters of the two forms are altogether similar, the chief 

 difference being found in the large lateral expansions of fig. 2 ; its rather more 

 attenuated extremities and less pronounced style of surface-sculpture, but these are all 

 characters which are well known to be often of only sexual importance. Had the two 

 forms occurred in the same dredging, I should not have hesitated at all to assign them 

 to the two sexes of the same species. 



[PL XVI. fig. 1, a-d, and fig. 2, a-d. la Shell of male (?) seen from left side, 

 16 from above, Ic from below, \d from front. 2a Shell of female (?) seen from left 

 side, 26 the same seen from above, 2c from below, 'id from the front. Magnified 60 

 diameters.] 



38. Cythere audei, G. S. Brady (PL XV. fig. 7, a-li). 



Cythere audei, Brady, Les Fonds de la Mer, torn. i. p. 162, pi. xix. figs. 12, 13. 

 Cythere rectangiilaris, Brady, Les Fonds de la Mer, torn. i. p. 153, pi. xviii. figs. 13, 14. 



Shell, seen from the side, oblong, quadi-angular, highest in front, the height being 



