158 CRUSTACEA. DECAPODA. 



Gen. 36. PACTOLUS, Leach. 

 Shell not spinous; beak long and entire; legs of moderate length, 



the first, second, and third pairs with a simple claw, the fourth 



and fifth pairs didactyle. 



P, Boscii, Leach. Beak on each side spinulose ; legs ciliate-punc- 

 tate Zool. Mis. ii. pi. 68. 



Gen. 37. LITHODES, Lat. Cancer, Lin. 

 Exterior antennae nearly half the length of the body, setaceous, 

 with the first two joints longer than the others ; exterior feet- 

 jaws with narrow subcylindric footsfalks ; eyes approximated at 

 the base; shell subtrigonal, rostrated anteriorly, very sca- 

 brous ; the last two feet extremely small. 



L. arclica, Lat. (C. maja, Lin.) Rostrum slender and bifurcated 

 at the end, spinous at the base ; margins of the claws with tufts 

 of hair ; body and legs with sharp spines. 4 inches long, 3^ broad. 

 Inhabits Northern seas. B. Pen. Brit. Zool. iv. pi. 8, fig. 1. 



f ' O 



FAMILY VI. NOTOPODA. 



The two or four posterior feet inserted on the back, or above the 

 line of the others. 



Gen. 38. DROMTA, Fab. Cancer, Lin. 



Exterior antennae small, inserted below the ocular peduncles ; 

 exterior feet-jaws with the third joint almost square ; forceps 

 large and strong, equal ; fourth and fifth pairs of feet inserted 

 on the back, shorter and didactyle ; shell oval, rounded, very 

 gibbous, hairy or bristly, as well as the feet and claws ; eyes 

 small, on short peduncles. 



The animals of this genus live in places where the sea is not very deep and among 

 rocks. They are almost always found covered with a species of Alcyonium, or with the 

 valves of shells, which they retain with their posterior feet as a kind of buckler or 

 shield, and oppose to the attacks of their enemies. 



D. Rumpkii, Fab. Shell subgibbous, rounded, covered with a brown 

 down, with five strong teeth on each side ; front tridentate ; toes 

 of the forceps rose-coloured. 2J inches long. Inhabits Medi- 

 terranean and Indian seas. Herbst, pi. 18, fig. 103. 

 Under the name of Dynomena, M. Latreille has instituted a new genus for a spe- 

 cies of Dromia brought from the Isle of France by M. Mathieu, the character of 

 which is having only two posterior feet on the back. 



Gen. 89. HOMOLA, Leach. Thelanope, Rafin. 

 Shell elongate, quadrate, slightly produced in front ; eyes large, 

 somewhat globose ; exterior antennae very long, inserted be- 

 neath the eyes, the first two joints long; exterior feet-jaws 

 with the internal peduncle composed of two long and narrow 

 joints ; palpi three-jointed ; legs ten ; first pair largest and di- 

 dactyle ; the three following pairs simple, and the claws spin- 

 ous, with the fifth pair monodactyle. 



3 



