PHOXUS PLUMOSUS. 149 



legs ; the coxa is very short, but the thigh is largely 

 dilated, and postero-inferiorly produced to a blunt point, 

 reaching as far as the wrist ; the inferior and posterior 

 margins are slightly crenated, each crenulation emitting 

 a solitary hair ; all the joints, except the finger, (which 

 is long, straight, and styliform,) are subequally short. 

 The caudal appendages are free from hairs or spines; 

 they terminate subequally, the antepenultimate pair 

 being slightly the longer, and the penultimate pair the 

 shortest. The branches are subequal, those of the last 

 pair being rather less pointed than those of the two 

 preceding pairs. The central piece is double, but not 

 so long as the peduncle of the posterior pair of caudal 

 appendages. 



The colour of the animal is corneous and transparent. 

 The structure of the tissue, under the microscope, is seen 

 to be minutely granular. 



Kroyer, in his description, says that a few spines exist 

 upon the third and fourth joints of the peduncle of the 

 inferior antennae in P. Holbolli, but that they are absent 

 in P. plumosus. In one specimen of P. Holbolli the hairs 

 upon the inferior antennae are scarcely robust enough to 

 be called spines ; whereas in P. plumosus there are a few 

 plumose hairs, of which Kroyer makes no mention. In 

 other respects the animals appear to correspond with 

 Kroyer's description, and we do not feel justified in sepa- 

 rating them upon such immaterial distinctions. The only 

 difference between P. plumosus and Stimpson's specimen 

 of P. fusiformis consists in the American specimen having 

 what the author of its description calls "more nails on 

 third and fourth legs." Now these so-called "nails" we 

 take to be the long lateral spines that impinge against 

 the sides of the fingers of the third and fourth pairs 

 of legs. 



