AMPHIPODA. 93 



the third being so small as to be confounded with those of the stem, 

 or forming; that of the base ; the superior are longer than the infe- 

 rior. All the feet are simple, or without forceps. Such is 



Dexamine, Leach(l). 



In those, the movable toe of the two forceps is bi-articulated. 

 The antennae are of equal length. 



Leucothoe, Leach. 



The antennae short, their peduncle formed of two joints; the four 

 anterior feet terminated in a stout forceps; toes of the two first bi-ar- 

 ticulated; those of the second pair consisting of a single and long 

 joint(2). 



Cerapus, Say. 



Large antennae, the peduncle consisting of three the superior 

 or four the inferior joints; the two anterior feet small, with a 

 uni-articulated toe; the two following terminating in a large triangu- 

 lar, smooth, dentated hand, with a bi-articulated finger. 



Ceraphus tubularis, Say, Journ. Acad. Nat. Sc. of Philad., I, 

 iv, 7 11; Desmar., Consid., XLVI, 2. It inhabits a little cy- 

 lindrical tube, and in this respect approaches the subsequent 

 subgenus. Very common at Egg Harbour, New Jersey, among 

 the Sertulariae on which it appears to feed. 

 Finally, the inferior antennae, sometimes much larger than the 

 superior, their stem consisting at most of four joints, have the form 

 of feet, and appear to serve, at least occasionally, as organs of pre- 

 hension. 



Kere the second feet are terminated by a large forceps. 



Podocerus, Leach. 

 Eyes very prominent(3). 



Jassa, Leach. 



Eyes not prominent(4). 



There, neither of the feet is terminated by a large forceps. 



(1) Cancer gammarus spinosus, Montag. , Trans. Lin. Soc, XI, p, 3; Desmar., 

 Consid , XLV, 6. 



(2) Cancer articulosus, Montag., Trans. Lin. Soc. VII, 6; Desmar., Consid., p. 

 263, XLV, 5. 



(3) Podocerus variegatus, Leach, Trans. Lin. Soc, XI, p. 361; Desmar., Consid. 

 p. 269. 



(4) Jassa pulehella, Leach, lb., p. 361; Desmar., Consid., p. 269. 



