OF DENISON UNIVERSITY. 7 



near the middle. It is about twice as long as high. Dorsal margin, 

 feebly convex; cephalic margin, convex; ventral margin, nearly 

 straight, slightly concave in the middle; caudal margin convex. 



Viewed from above [fig. 2] the shell is sub-elliptical, inequivalve, 

 one valve overlapping the other in front Shell widest near the mid 

 die. Cephalic extremity about as wide as the caudal. All margins 

 convex. Hinge line straight. 



Viewed from below [fig 3] shell presents the same outline as 

 when viewed from above, but the line of contact of the two valves is 

 sinuated. 



Viewed from the end, the shell is oval, widest in the middle, 

 ventral margin about as wide as dorsal. 



Antennules typical for the genus. 



Antennae of female [fig. 4] composed of four joints, the joints 

 diminishing in size from the most proximal to the most distal joint. 

 The most proximal joint bearing at about the middle of its ental 

 margin a long seta. The next joint bears at about the middle of its 

 ental margin the usual biarticular sensory hair and at its disto- ental 

 angle a moderately long plumose seta, this seta extends to about the 

 base of the terminal claws. From the base of the penultimate joint 

 arise five very long non-plumose setae, these setae extending far be- 

 yond the tips of the terminal claws. At the middle of its ental 

 border this joint bears a short seta and opposite this on the ectal bor- 

 der there is a slightly longer seta. From the disto-ental angle of this 

 joint arise two short seta. From the ectal half of its distal margin 

 arise two long claws ; one of these claws extends beyond the tip 

 of the claws springing from the terminal joint, while the other extends 

 nearly to the tip of those claws. At the extremity of the terminal 

 joint there are two large claws and two short setae ; one of these seta 

 is located at the disto-ental angle and the other at the disto-ectal 

 angle of the joint. 



First foot of female [fig. 5] long and slender, composed of five 

 joints. The most proximal joint large, the broadest of all. The 

 next joint the shortest of all. The antipenultimate joint about as long 

 as the most proximal, but more slender. From the margin of this 

 joint arise two short setae. From the disto caud il angle of this joint 

 arises a long seta which extends to beyond the base of the terminal 

 claws. From near the disto-cephalic angle of this joint arises a short 

 seta. Along the cephalic margin of the penultimate joint there is a 

 longitudinal row of fine hairs. From the disto caudal angle of this 

 joint arises a seta medium length. From the extremity of the terminal 



