414 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



anterior end sliort and roundly pointed ; the posterior longer, obliquely pro- 

 duced, rounded ; resilium subumbonal, short, internal, left valve with two strong 

 divaricating cardinal lamellae, one on each side of the resilium, rather short and 

 prominent ; right valve with the margins so produced as to enclose the opposite 

 pair ; interior of valve polished, with a yellowish flush ; margins entire and also 

 the pallial line. Longest dimension, 2.2 ; width at right angles, 1.7 ; diameter, 

 1.4 mm. 



Dredged with the preceding species in Magellan Strait. U. S. N. Mus. 

 110,714. 



A small but rather solid and characteristic little species. It is named in honor 

 of the senior author of the MoUusks of Cape Horn. 



Rochefortia rochebrunei Dall, n. sp. 



Plate 17, figure 5. 



Shell small, subquadrate, compressed, white, inequilateral, with low, rather 

 anterior beaks, and a pale yellowish periostracum ; anterior dorsal margin straight, 

 sloping, anterior end rounded, basal margin nearly straight ; posterior dorsal mar- 

 gin slightly convexly arcuate, near the end obliquely descending to a rounded 

 point; outer surface somewhat irregularly concentrically striated; interior pol- 

 ished ; resilium subumbonal, internal, with on each side of it a diverging lamella, 

 stronger in the left valve. Length, about 4.5; height, 3.7; anterior end, 1.5 ; 

 diam. 1.5 mm. 



Dredged in Magellan Straits with the two preceding species. U. S. N. Mus. 

 110,713. 



This species is named in honor of the junior author of the MoUusks of Cape 

 Horn. 



(Ctclodonta) 



Cardiacea. 



Cardiidae. 



PROTOCAKDIA Beykicu. 



This genus, of Mesozoic origin, is not sparsely represented in the recent fauna 

 of the deep sea, and some of the most lovely of molluscan gems of the ocean 

 are found among these species. But the extremely fragile spinosc ornamonla- 

 tiou of tlie posterior area is almost always wanting, as a touch is enough to detach 

 it even from the living shell. 



