AMPHIPODA. 221 



The species best known and the type of this subgenus is the 

 Cancer pidex,L. ; Sqid/la pulex, De Geer, Insect., VII, xxxiii, 

 1,2. It inhabits brooks, &c. The other species are marine * 

 The antennae of the folloAving, as in all the other Amphipoda, are 

 simple or without appendages. 



Melita, Leach. 



The second pair of feet, in the male, terminated by a large com- 

 pressed forceps, the toe folding under its internal surface; tlie an- 

 tennae nearly equal in length ; a small foliaceous appendage on each 

 side of the posterior extremity of the body f . 



M^RA, Leac/t. 



Tlie second feet in the males terminated as in the Melitse, but tlie 

 toe folds under tlie inferior edge of the forceps and is not concealed. 



The superior antennae are longer than the inferior, and the foliace- 

 ous appendages of the posterior extremity of the body are Avant- 



Amphithoe, Leach. 



The four anterior feet nearly similar in both sexes ; tlie penultimate 

 article or hand proper, ovoid §. 



Pherusa, Leach. 



The Pherusse only differ fj-om the preceeding subgenus in the hand 

 of the forceps, which is filiform ||. 



There, the peduncle of the antcnnce is only composed of tAVo joints, 

 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 inferior. 

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



Dexamine, Leach'^. 

 In those, tlie moveable 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- 



* See Desmar., Consid., p. 265, 207. 



t Cancer pcdmafus, Montag., Trans. Lin. Soc, VII, p. 69; Encyclnp. Method., 

 Atl. d'Hist. Nat.. CCCXXXYI, 31 ; Desmar., Consid., XLV, 7. 



X Cancer gcnnmarus grosimanKs, Montag., Trans. Lin., Soc, IX, iv. 5 ; Defsmar. 

 Consid., p. 264. 



§ Cancer ruhricafus, Montag., Trans. Lin. Soc, IX, p. 99 ; Encyclop. Method., 

 Atl. d'Hist. Nat., CCCXXXYI, 33 ; Desmar., Consid., XLV, 9',—Omsnts canceUiis, 

 Pall., Spic Zool. Fascic, IX, iii, 18; Gamniurus cancellus. Fab. 



II Pherusa fiisicvia, Leach ; Trans. Lin. Soc, XI, p. 360 ; Desmar., Consid., 

 p. 268. 



^ Cancer gammarus spinosus, Montag., Trans. Lin. Soc, XI, p. 3 ; Desmar., 

 Consid., XLV, 6. 



