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



Only a few valves of Cythere scalaris were noticed in a dredging from Torres Straits, 

 lat. 11° 26' S., long. 140° 3' E., 155 fathoms (Station 185), and in a sounding from 100 

 fatlioms (Station 305). 



[PL XXI. fig. 8, a-c, a Left valve (young), h right valve (adult) seen from side, c the 

 same from above. All magnified 50 diameters.] 



45. Cythere pachardi, n. sp. (PI. XIX. fig. 2, a-d). 



Shell, seen from the side, oblong, rather higher in front than behind, anterior extre- 

 mity obliquely rounded, posterior rounded off" above, produced below the middle ; dorsal 

 margin sloping backwards from the front, almost in a right line, inferior sinuated about 

 the middle ; greatest height equal to more than half the length ; seen from above, the 

 outline is oblong, with nearly parallel sides and broad truncated extremities ; the lateral 

 margins are slightly sinuated in the middle, and converge somewhat suddenly towards 

 the extremities ; width equal to half the length ; the end view is irregularly ovate, height 

 considerably greater than the width. Surface of the shell honeycombed with rather 

 large angular cavities, and having also several sinuous ridges, the most conspicuous of 

 which runs parallel with the ventral margin, and makes an upward turn a little in front 

 of the posterior margin. Length, 1-5 2d of an inch ('48 mm.). 



This species, which occurred only in a dredging from Station 187, ofi" Booby Island, I 

 have pleasure in naming after Dr A. Packard of Cambridge, U.S., a naturalist well known 

 for his valuable contributions to the knowledge of many branches of invertebrate zoology. 



[PL XIX. fig. 2, a-d. a Shell seen from left side, 6 from above, c from below, d from 

 front. Magnified 60 diameters.] 



46. Cythere fldbellicostata, n. sp. (PL XIII. fig. 6, a-h). 



Shell of the female, seen from the side, quadrangular, highest in front, height ecpal 

 to more than half the length ; anterior extremity broad and obliquely rounded, posterior 

 truncated, produced below the middle and slightly emarginate above ; dorsal margin 

 gibbous in front, thence sloping with a slight convexity backwards, and ending in a sharp 

 angle ; ventral margin nearly straight ; seen from above, ovate, with nearly equal, broadly 

 truncated extremities; width equal to about half the length; the sides are gently curved, 

 converging gradually towards the front and more suddenly behind ; end view ovate, with 

 irregular convex margins, broad at the base, and slightly tapered to the apex. The 

 surface of the valves is marked throughout with large, irregularly-shaped, angular cavities, 

 separated from each other by sharply-cut ridges, which on the hinder half assume a 

 radiating or fan-like arrangement. The shell of the male (figures e-h) presents the usual 

 elongated, compressed, and angular form. Length, l-50th of an inch ("5 mm.). 



Dredged in Simon's Bay, South Africa, in a depth of 15 to 20 fathoms (Station 

 140). 



