38 CRUSTACEA. 



claws are short and thick, and the other feet very flat; the fourth 

 pair, and then the third are longer than the others; tarsi spinous. 



Plagusia, Lat. 



The mediate antennse lodged in two longitudinal and oblique 

 fissures traversing the whole thickness of the middle of the clypeus(l). 

 They are inferior or covered by this part in 



Grapsus, Lam. 



Where the shell is somewhat wider before than behind, or at least 

 not narrower, while in the Plagusiae it widens from before back- 

 wards. 



The Grapsi are found throughout all parts of the globe, but are 

 more particularly abundant in the vicinity of the tropics. They are 

 not seen in Europe beyond 50 of latitude. If I mistake not they are 

 called Ceriques at Martinique. Marcgrave has figured some Brazi- 

 lian species by the names of Aratu, Arahc-pinima (Grapsus cruen- 

 tatus, Lat.) and Carava-una. At Cayenne they are called JRaga- 

 beumba, or soldier. 



These animals conceal themselves during the day under stones, 

 &c, at the bottom of the sea. I have been informed that some of them 

 even climb up the trees on its shores and hide beneath their bark. 

 The broad and flattened form of their body and feet enables them to 

 support themselves for a moment on the surface of the water; they 

 always walk sideways, sometimes to the right and at others to the 

 left. Certain species inhabit rivers within the bounds of tide water, 

 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. Their habits are similar to those of other 

 carnivorous Crustacea(2). 



G. varius, Lat.; Cancer marmoratus, Fab.; Oliv., Zool., 

 Adr., II, 1; Cancre madre, 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 projec- 



(1) P. depressa, Lat.; Herbst., Ill, 35; P . clavimuna, Lat., Herbst, lix, 3; 

 Desmar., Consider., XIV, 2. The tail appears to me to consist of but four dis- 

 tinct segments. The third, however, presents one or two deep and transverse 

 lines. In the Grapsi there are seven segments, the third of which has an angular 

 dilatation on each side of its base. 



(2) See Bosc, Hist. Nat des Crust. 



