PHOXUS SIMPLEX. 141 



peduncle is very sliort ; and the flagellum is scarcely 

 longer ; the secondary appendage consists of but three 

 articuli, and is nearly as important as the primary, wliich 

 is formed of but four. The inferior antenna} are about 

 as long again as the head, and three times as long as the 

 superior ; the peduncle does not reach as far as the 

 apex of the projecting head ; and the flagellum, which 

 consists of about ten or twelve articuli, has each articu- 

 lus almost as broad as long. The coxae of the arms and 

 first two pairs of walking legs are very large, broad, and 

 much deeper than the respective segments of the body ; 

 the three anterior are furnished, towards the posterior 

 portion of the inferior margin, with four simple hairs, 

 which number appears to us to be persistent, as five are 

 to P. HolholH, and a greater number to P. plumosus ; 

 the arms are subcqual, the first pair being rather the 

 smaller ; the wrist is short, and the hand twice as long 

 as broad ; the inferior margin runs parallel with the 

 superior, but is not quite so long ; the palm is slightly 

 oblique, and defined by a small tooth at the inferior 

 angle; the finger is of the same length as the palm. 

 The second pair of arms vary but little in form from 

 the preceding ; the hand is a little larger, it is rather 

 broader towards the base, both margins are convex, the 

 inferior is about one-third shorter than the superior ; 

 the palm is much more oblique than that of the first 

 pair, it is also slightly convex, and defined by a larger 

 tooth at the inferior angles : the finger is slightly curved, 

 and is about the length of the palm. The walking legs 

 are rather slender. The first two pairs have the fingers 

 rather long and straight. The fourth pair of these legs 

 are longer than the third, but the fifth are much shorter 

 than either, and apparently useless ; the squamiform 

 thigh is larger than that of the preceding legs, and 



