72 CRUSTACEA. 



have but a single tooth in place of the index or immovable finger, 

 and that which is movable is bent and hooked. 



The superior or intermediate antennae have but two threads. 

 The second feet are folded up, and are more or less distinctly bifid 

 or didactyle at their extremity; neither of the joints is annulated. 

 The rostrum is very short. 



We do not separate the Egeon, Risso, or the Pontophilus, Leach, 

 from Crangon. In the former, the last joint of the external foot- 

 jaws is twice the length of the preceding one, while in the latter 

 they are equal. The second feet of the Egeones are shorter than the 

 third and the smallest of the whole number, whilst in Crangon their 

 length is the same. Besides, as the number of species is very 

 limited, this generic distinction becomes the less necessary. 



C. vulgaris, Fab.; Roes., Insect., Ill, lxiii, 1,2. (The Shrimp), 

 about two inches long. It is smooth, of a pale glaucous green, 

 dotted with grey. That part of the thorax which supports the 

 third pair of feet, projects in a point. This species is very com- 

 mon on the oceanic coast of France, where it is vulgarly called 

 the Cardon. It is taken there annually in nets. Its flesh is deli- 

 cate, and highly esteemed. In the same locality, though rarely, 

 according to M. Brebisson, is found the C. ponctue de rouge, of 

 Risso; but I consider it, with him, as a mere variety. The C. 

 loricatus Egeon loricatus, Risso; Cancer cataphractus, Oliv., 

 Zool., Adriat., Ill, 1, has three longitudinal and dentated ridges 

 on the thorax. 



Northern seas produce a large species, the Crangon boreas, 

 Phipps., Voy. to the North Pole, pi. xi, 1, Herbst. XXIX, 2. 



Processa, Leach. JVika, Risso. 



One of the two anterior feet simply terminating in a point, the 

 other in a didactyle claw; the two following are unequal, slender, 

 and also didactyle. One of these second feet is very long, its carpus 

 and the preceding joint being annulated, a character which on the 

 other foot is only found in the first of these joints. The fourth pair 

 of feet are longer than the preceding and two following ones. The 

 superior antennas have but two threads. 



P. edulis; Nika edidis, Riss., Crust., Ill, 3, is of a flesh colour 

 dotted with yellowish; a line of small yellow spots in the middle. 

 The anterior extremity of the shell is furnished with three 

 sharp points, the intermediate of which, or the rostrum, is the 

 longest. The two anterior feet are equal in size, the right one 

 forming a forceps. This species is found during the whole year 



