98 THE YOYAGE OF H.M.S. CHALLENGER. 



length, and equal throughout ; anterior extremity slightly rounded, and bordered with a 

 row of short, broad, and blunt teeth ; posterior extremity irregularly rounded, and more 

 or less broken into spine-like processes ; dorsal margin straight or nearly straight, 

 angulated at its junction with the posterior extremity, ventral slightly convex ; seen 

 from above, the outline is regularly ovate, with slightly jagged edges, greatest width 

 equal to the height, and situated in the middle ; extremities broadly rounded ; end 

 view very broadly ovate, almost cordate. The surface of the shell is granular in 

 appearance, and is marked throughout by closely -packed, deep, angular fossse ; the 

 spinous armature is very variable in its degTee of development, and as a rule is depend- 

 ent largely upon age and sex, stronger in males than in females. Male specimens are 

 figured at e, f, g, and besides being strongly spined are larger and of more slender pro- 

 portions than the females. Length (of females), l-38th of an inch ('66 mm.). 



Found in anchor-mud from a depth of 7 fathoms. Hong Kong Harbour, and in 

 a dredging from 15 fathoms. Inland Sea, Japan (Station 233Z>). The specimens 

 described in Les Fonds de la Mer were dredged at the north point of Java ("North 

 Watcher "). 



[PL XXV. fig. 2, a-g. a Shell of female seen from left side, h from above, c from 

 below, d from front, e shell of male seen from left side, _/ from below, g variety of male, 

 right valve seen from side. All magnified 50 diameters.] 



65. Cythere cribriformis, G. S. Brady (PI. XIX. fig. 3, a-d). 



CytMre crihriformis, Brady, Trans. Zool. Soc, 1865, vol v. p. 379, jjI. Ixi. fig. 6, a-d. 



Shell tumid, subovate ; seen from the side, oblong, subquadrangular, scarcely higher 

 in front than behind, height ecpal to more than half the length ; anterior extremity 

 moderately rounded ; posterior narrower, and well-rounded ; dorsal margin elevated into 

 an angular prominence over the anterior hinge, behind which it is almost straight ; 

 ventral slightly convex ; the entire circumference, especially the anterior and posterior 

 margins, is irregularly broken and dcntated ; seen from above the outline is broadly 

 ovate, strongly jagged, or dentated, wadest behind the middle, greatest width equal to 

 nearly two-thirds of the length, very broadly rounded behind, narrower in front ; end view- 

 very broad, the width greater than the height, centrally emarginate both above and below. 

 The surface-sculpture is very similar in character to that of Cythere darunni, but is more 

 strongly marked, and there are no distinct marginal spines, the marginal irregularities 

 being only such as are produced by the general roughness of the surface ; the edges of 

 the valves are strongly depressed on the ventral, and more especially on the dorsal, aspect. 

 Length, l-40th of an inch ("65 mm.). 



This species was noticed only in anchor-mud from Hong Kong Harbour, 7 fathoms. 



[PI. XIX. fig. 3, a-d. a Shell seen from left side, h from above, c from below, d from 

 front. Magnified 60 diameters.] 



