no. 1663. THE ISOPOD — ANCINUS DEPRESSUS — RICHARDSON. 177 



angles more or less produced, and they are all bent downwards 

 about the middle almost at right angles with the segments. On the 

 ventral side they are also produced in the form of a plate, covering 

 the proximal extremity of the legs. 



The abdomen is composed of two distinct segments. The first is 

 short, not as long as the last thoracic segment, and has no suture lines 

 indicating other coalesced segments. The terminal segment is trian- 

 gular in shape with the apex appearing somewhat truncate, owing 

 to the sides of the segment being turned downward and inward, so 

 that on the ventral side a funnel-like opening is formed. The uropoda 

 are composed of a small rounded peduncle and a single slender, 



Fig. 7. — A n c i n u s 

 depressus. Fourth 

 pleopod. X 41. 



Fig. 8. — Ancinus 

 depressus. 

 Fifth pleopod. 

 Outer branch. 

 X 41. 



Fig. 9. — Ancinus de- 

 pressus. Fifth 

 tleopod. Inner 



BRANCH. X 41. 



movable branch, tapering and acute at the extremity. This branch 

 extends to the extremity of the last abdominal segment. 



The first pair of legs are subschelate and have the propodus very 

 much enlarged. All the other legs are ambulatory. 



The first pair of pleopoda are small, longer than wide and com- 

 posed of a single branch furnished with long hairs. This branch is 

 widely separated from the corresponding branch of the opposite side. 

 The second pair of pleopoda are large, double branched, the two 

 branches being placed side by side and attached to the peduncle, so 

 that a sort of operculum is formed, completely covering the following 

 pleopoda. The third pleopoda have the endopod slightly longer 

 than the exopod; both branches without marginal setae. Fourth 

 pleopoda with endopod and exopod of nearly equal length, and with- 

 out marginal seta3. Fifth pleopoda with both branches un jointed 

 and without marginal seta?. 



Owing to the difference in the structure of the pleopoda, this genus 

 remains alone the type of the family Anciniidce. Bathycopea Tatter- 

 sall cannot be retained in the family. 

 Proc. N. M. vol. xxxvi— 09 12 



