DECAPOD A. 177 



but most frequently live on their banks or on land. They assemble 

 in great numbers, and when any one appears among them, they hurry 

 to the water with a tremendous noise, caused by striking one claw 

 against the other. I'heir habits are similar to those of other carni- 

 vorous Crustacea *. 



G. variii<;, Lat. ; Cancer marmoratus. Fab. ; Oliv., ZooL, 

 Adr., II, 1 ; Ca/icre mac/;-e. Rondel. ; Herbst., XX, 114. Size 

 middling ; nearly square, hardly broader than long ; yellowish or 

 livid ; greatly elongated above, and marked with numerous fine 

 lines and points of a reddish brown ; four flattened projections 

 arranged transversely at the base of the clypeus, and three teeth 

 at the anterior extremity of each lateral edge. The tarsi are 

 spiny. The 



G. porte-pinceau ; Cuv. Regne Anim., IV, xii, 1; Rumph., 

 Mus. X, 2; Desraar., Consider., XV, 1, is remarkable for the 

 numerous lung and blackish hairs with which the superior sur- 

 faces of the fingers are furnished. The tarsi are without spines, 

 a character exclusively peculiar to this species. It is found in the 

 East Indies f . 



In our fourth section or the Orbiculata J, the shell is either sub- 

 globular, rhomboidal, or ovoid, and always very solid; the ocular pe- 

 dicles are always short or l)ut slightly elongated ; the claws of un- 

 equal size according to the sex, those of the males being largest ; there 

 are never seven complete segments in the tail ; the buccal cavity 

 grows gradually narrower towards its superior extremity, and the 

 third joint of the external foot-jaws always forms an elongated 

 triangle. The posterior feet resemble the preceding ones, and neither 

 of the latter is ever very long. In the 



CoRYSTES, Latr., 



The shell is an ovoidal oblong, and crustaceous ; the lateral antennae 

 are long, projecting and ciliated ; ocular pedicles of a mean size and 

 separated ; third joint of the external foot-jaws longer than the pre- 

 ceding one, with a visible emargination for the insertion of the next. 

 The tail is composed of seven segments, the two middle ones oblite- 

 rated in the males. 



A species — Cancer personatus, Hei-hst., XII, 71) 72; Leach, 

 Malac. Brit., VI, 1, is known on the coast of France. The 

 lateral edge of its shell is marked with three notches on each 

 side. 



A second was brought from the Cape of Good Hope by the 

 late Delalande. 



* See Bosc, Hist. Nat. des Crust. 



f See the Article Playiisie, Encyc. Method., aad the Histoire des Animaux sans 

 vert&bres of Delamarck, genus Grapse. 



X The Orythice and the Dorippes, in a natural series, would, in my opinion, belong 

 to this section, and lead to the Corystes ; their shell is a truncated ovoid. 



VOL, HI. N 



