210 ' CLASS CRUSTACEA. 



sexes, and the last articulation but one, or the hand, is ovoid. 

 {Cancer rubricaius, Montagu.) 



Pherusa, Leach, 



Which do not differ from Ampithoe, except that the hands of 

 the claws are filiform. {Pherusa fucicola, Leach.) 



Sometimes the peduncle of the antennae is composed of 

 only two articulations — (the third, from its smallness, being 

 confounded with those of the stem, or forming that of its 

 base) ; — the superior are longer than the inferior ; all the feet 

 are simple, or without pincers. Such are 



Dexamine, Leach. 



In those, the talon, or mobile finger of the two pincers, is 

 biarticulate ; the antenna3 are of equal length. (^Cancer gam- 

 mams spinosus, Montag.) 



Leucothoe, Leach, 



Have the antennae short, and their peduncle with two 

 articulations ; the four anterior feet strongly terminated in a 

 pincer, the talons of the two anterior biarticulate ; those of 

 the second pair with a single articulation and long. {Cancer 

 articulosus, Montagu.) 



Ceeapus, Say., 



Whose antennae are large, with the peduncle in the upper of 

 three, in the lower of four articulations ; the two anterior feet 

 are small, with a talon of a single articulation ; and the two 

 following terminate in a large triangular hand, smooth, den- 

 ticulated, with the talon biarticulate. [Cerapus tuhula- 

 ris, Say.) 



Sometimes the low^er antennae, much larger than the upper, 

 and whose stem is composed at most of four articulations, 

 have the form of feet, and appear to serve, at least occasionally, 

 as organs of prehension. 



