164 CRUSTACEA. DECAPODA. 



T. scorpionoideS) Lat. Rostrum with the anterior margin granu- 

 lated ; thighs with two rows of small spines on their anterior 

 margin ; claws carinated longitudinally, and serrated. 6 or 7 

 inches long. Inhabits Indian seas. Herbst, pi. 62. 



Gen 54. GEBIA, Leach. Cancer, Mont. 

 Two anterior legs equal, subdidactyle, with the thumb short ; 

 interior antennae with an elongated peduncle, the second joint 

 shortest, the third longest and cylindrical ; exterior feet-jaws 

 with the third joint of the internal footstalk shortest ; tail 

 with broad lamellae, the middle one quadrate. 



G. deltaura, Leach. Abdomen with the back membranaceous ; 

 tail with the apex of the exterior lamella dilated, and somewhat 

 rounded ; interior one truncated and formed like the Greek del- 

 ta. Coasts of Britain., deep in the sand. Lin. Trans, xi. 342. 



Gen. 55. Axius, Leach. 



Four anterior legs didactyle ; anterior pair largest and some- 

 what unequal ; the others furnished with a compressed claw ; 

 interior antennae with a three-jointed peduncle ; exterior feet- 

 jaws with the two first joints equal ; tail broad, the inter- 

 mediate lamella triangular, elongate. 



A. Slirhynckus, Leach. Rostrum margined, the middle carinated ; 

 thorax behind the rostrum with two elevated abbreviated lines, 

 notched behind. Inhabits British seas. Lin. Trans, xi. 343. 



Gen. 56. CALLIANASSA, Leach.. 



Pour anterior legs didactyle ; anterior pair largest ; fourth and 

 fifth pairs spinous ; internal antennae with an elongate bi- 

 articulate peduncle ; exterior feet-jaws with the second joint 

 of the internal footstalk largest and compressed ; tail with 

 broad lamellae. 



C. subterranea, Leach. Shell with the rostriform process with one 

 longitudinal ridge, the point rounded. 2 inches long. Inhabits 

 British coasts, in the sand. Lin. Trans, xi. 343. 



Gen. 57. NEPHROPS, Leach. Astacus, Perm. 

 External antennae with the first joint of the peduncle furnished 

 at its apex with a produced scale ; eyes reniform, much thick- 

 er than the peduncle ; six didactyle legs ; anterior claws very 

 long, angular, and spinous. 



N. Norvegicus, Leach. Shell somewhat spinous in front, and the 

 abdomen with hairy areolae. Inhabits Northern seas, and found 

 in the Frith of Forth during the summer months. 9 inches long. 

 Pen. Brit. Zool. iv. pi. 13, fig. 1. 



Gen, 58. ASTACUS, Lat. Cancer, Lin. 



Four unequal antennae in the same transverse line, the two in- 

 termediate shortest, and deeply bifid, the lateral ones simple 



