356 



Transactions. 



first ; flagellum as long as peduncle, and containing about 8 joints. Second 

 antenna (fig. 2, ant^) fully one-third the length of the body; penultimate 

 joint of peduncle rather shorter than the ultimate, both rather broad ; 

 flagellum stout, subequal in length to the peduncle, of about 20 joints. 



Mouth parts apparently not presenting any distinctive features. 



First gnathopod (fig. 3, gn^) with side plate subtriangular, somewhat 

 produced downwards anteriorly, its lower margin with a few stout setae, 

 its inner surface with an irregular row of more slender setae extending 

 from the insertion of the basal joint to the infero-anterior angle ; merus 

 with a small rounded pellucid process, carpus much longer than the propod, 

 the pellucid area on each marked ofi from the rest of the joint by a row 

 of stout setae, palm transverse, finger not extending beyond the true palm. 



Second gnathopod (fig. 3, gn^) with side plate produced at about the 

 middle of the posterior margin into a subacute point, basal joint not much 

 expanded, merus and carpus very short, propod very large, widening 

 distally, anterior and posterior margins without setae, palm only slightly 



Fig. 3. — Orchestia miranda, male, gn^, first gnathopod ; gn'^, second gnathopod. 



oblique, straight or a little convex, provided with a double row of short 

 stout setae, finger strong with an enlargement at about its proximal third, 

 end curved and fitting into a short groove at the end of the palm. 



First and second peraeopoda alike and presenting no special features, 

 the side plates subrectangular with rounded corners, posterior margin in 

 each produced into a subacute process, setae on the various joints few and 

 short, two or three stout ones on anterior border of propod at base of finger. 

 Third peraeopod (fig. 4, prp^) subequal in length to the two preceding, 

 side plate with anterior lobe as deep as the fourth, basis broadly expanded, 

 its posterior margin convex and serrate, merus and carpus somewhat 

 widened, about twice as wide as the propod. Fourth peraeopod (fig. 4, prp*) 

 with basis similar to that of the third, ischium normal, merus widening 

 greatly toward distal end, which is rather oblique and nearly as wide as 

 the joint is long, carpus forming a large rectangular plate with rounded 

 corners, nearly as broad as long, propod and finger normal, not expanded. 



