inn.] 



NATURAL SCIENCES OF PHILADELPHIA. 



523 



A NEW EAST INDIAN EUCIROA. 



BY H. A. PILSBRY. 



In a collection of invertebrates from the East Indies there was a 

 single right valve of Euciroa, differing from all described species 

 of the genus by its great size and by the orbicular shape. 

 Euciroa dalli n. sp. 



The shell is rather plump, subcircular, slightly inequilateral, the 

 length and height about equal. Anterior margin broadly rounded; 

 posterior margin obtusely subangu- 

 lar near the base, with a shallow 

 emargination above the angle. 

 Dorsal and ventral margins about 

 equally convex. Beaks small, slightly 

 projecting above the margin and 

 turned forward. The exterior is 

 evenly convex except for a low, 

 rounded ridge running to the pos- 

 terior angle, the area above it being- 

 flattened. Surface sculptured with 

 many unequally spaced low radii 

 bearing small, well-raised pustules, 

 the slightly concave intervals be- 

 tween the radii irregularly, rather 

 closely and minutely granular. The 

 posterior flattened area has no 

 radial rows of pustules, but is 

 densely granular. Lines of growth 

 are scarcely visible except near the 

 basal and posterior margins, where 

 they are rather strong and irregular. 

 It is light buff with some reddish 

 stains. 



The interior is brilliantly pearly, with some iridescence of the 

 silvery surface chiefly towards the margins. The adductor muscle 

 impressions are large and deep. Within the smooth pallial band 

 there is a broad roughened area. The lower margin of the valve 



E. dalli. (About f natural size.) 



