134 THE VOYAGE OF H.M.S. CHALLENGER. 



acuminate, the posterior strongly mucronate ; end-view subtriangular, height greater 

 than the width, widest at the base, apex truncate. Surface of the shell marked with 

 distant rounded punctures which are arranged in curved longitudinal rows. Length, 

 l-50th of an inch ('5 mm.). 



Dredged in Simon's Bay, South Africa, in. a depth of 15 to 20 fathoms. A very 

 distinct species somewhat like the British Cytherura jproducta, but more robust and 

 much higher in proportion to its length, distinctly sculptured also, — the British species 

 being quite smooth. 



[PI. XXXII. fig. 9, a-d. a Carapace seen from left side, h from above, c from below, 

 d from front. Magnified 60 diameters.] 



8. Cytherura costellata, n. sp. (PI. XXXII. fig. 7, a-d). 



Carapace elongated, compressed ; seen from the side oblong, narrow, highest in the 

 middle, height equal to half the length, anterior extremity evenly rounded, posterior 

 obliquely truncate, and produced above the middle into a prominent conical beak ; dorsal 

 margin gently and evenly arched, ventral straight ; seen from 'above, oblong, subhexa- 

 gonal ; sides straight and parallel, converging rather abruptly to the extremities, both of 

 which are strongly mucronate, width less than the height ; end view pentagonal, much and 

 irregularly emarginate. Shell-surface ornamented with numerous waved and anastomos- 

 ing ribs forming an irregularly reticulated pattern. Length, l-50th of an inch ('5 mm.). 



Dredged in Balfour Bay, Kerguelen Island, in 20 to 50 fathoms (Station 149). 



[PL XXXII. fig. 7, a-d. a Carapace seen from left side, h from above, c from below, 

 d from front. Magnified 60 diameters.] 



9. Cytherura clausi, n. sp. (PI. XXXII. fig. 8, a-d). 



Carapace tumid ; seen from the side, oblong, height nearly the same behind and 

 before, and equal to half the length, anterior extremity rounded, posterior produced 

 above the middle into a large, conical, truncated beak, dorsal margin slightly arched, 

 ventral straight ; seen from above, ovate, widest in the middle, tapering gradually to the 

 anterior extremity, which is broadly pointed, posterior extremity rounded, with a large 

 central mucro ; end view subtriangular, width and height about equal. Surface of the 

 valves honey-combed with numerous irregularly angular cavities. Length, l-50th of an 

 inch ("5 mm.). 



Dredged in Simon's Bay, South Africa, 15 to 20 fathoms (Station 140). 



[PI. XXXII. fig. 8, a-d. a Carapace seen from left side, h from above, c from below, 

 from front. Magnified 60 diameters.] 



10. Cytherura cryptifera, n. sp. (PI. XXXII. fig. 4, a-c). 



Valves, as seen from the side, oblong, subrhomboidal, a little lower in front than 



