K. J. Bush — 3/o//u.'«'<i of C(fj>e Hdltaras. 475 



Length of one of the hxrgest specimens, 16"""; height, across cen- 

 ter, 8"'"' ; thickness, about 3"'"\ 



Separate valves were very abund.int in 7 to 48 fathoms; and a few 

 young living S|)ecimens were found in 15 to 17 fathoms. 



Clidiophora, sp. indet. 



A single left valve, (No. 45,202), quite distinct from G. trilineata^ 

 or any species known to me, occurred at station 2275, in IG fathoms. 



Valve small, thin, very much distorted. Beaks minute, bending 

 strongly outward, situated far over toward the posterior end ; ante- 

 rior dorsal margin curving abruptly upward from the beak and then 

 continuing in a straight line ; posterior dorsal margin very short, 

 oblique and slightly concave, forming an acute angle at its junction 

 with the ventral margin. Ventral margin much curved, the greatest 

 curvature near the anterior end, where it bends inward toward the 

 beaks, forming a very slight rostrum. Surface very rough. Two dis- 

 tinct, impressed lines or grooves, parallel to the dorsal margin, extend 

 from the beaks to the anterior end ; above the second there is a 

 broad, nearly flat, dorsal area ; below it the valve is very convex and 

 the surface is cut by fi-om thirteen to fifteen very conspicuous, unequal, 

 and unequally distant, concentric grooves, becoming dee])er and farther 

 apart toward the ventral margin and scarcely visible on the posterior 

 surface, which is concave and I'oughened by the lines of growth. Inte- 

 rior lustrous and very pearly. The two exterior, dorsal grooves show 

 as two distinct ridges, and four of the deepest, exterior, concentric 

 grooves appear as elevated lines, with broad, concave interspaces. 

 The edge of the valve along the entire length of the anterior dorsal 

 margin is bent in at right angles and forms a gradually widening 

 area. Hinge consists of three distinct, thin, oblique, unequal, diver- 

 gent teeth. The first is a very oblique, long and narrow, angular 

 ridge, having a shallow, elongated cartilage-pit in its posterior side. 

 The second, directly under the beaks, is very much shorter, broader, 

 more elevated, and less oblique, and the third is a very slightly ele- 

 vated ridge extending from the beak to the posterior muscular scar. 

 Scars rather distinct, pallial line not visible. 



Macha Cumingiana (?) Dkr. 



Macha Cumingiana Dunker, Proc. Zool. Soc. London, p. 425, 1861. 

 Macha strigillata (Linne), var. (?) Bush, Report U. S. Com. Fish and Fisheries, 

 p. 86, for 1883, 1885. 



Shell moderately large, thin, convex, long and narrow, with broadly 



