DKCAl'Ol'A. 171 



Two naturalists, travellers of the, government, prematurely taken 

 from tli" M'iences, Delande and Leschenault-do-Latour. discovered 

 two other ope ifl was collected by the first in his travels to 



the south of Africa, and the other by the second in the mountains of 

 Ceylon. 



Tin- Cancer senex of Fabricius (Herbst., XL, 5), should, in my 

 opinion, be referred to the same subgenus. It inhabits the East 

 I., .lies. 



A species peculiar to America, the Thelphusa serrata, Herbst., 

 X, ii, is iro|K>rtionably wider and flatter than the others, pre- 

 inu certain characters which seem to indicate a particular 

 division *. 



Other Quadrilatcra having, like the preceding ones, the fourth 

 joint of thr external foot-jaws inserted in the external extremity of 

 the previous joint, differ from them in the trapezoidal, transverse and 

 widened form of the fore-part of the shell, as well as in their ocular 

 pedicles, which, like those of the Podophthalmi, are long and slender, 

 extending to the anterior angles, and inserted near the middle of the 

 front. Tin- claws of the males are long and cylindrical : such is the 



GONOPLAX, Leach. 



Two species of which are found in European seas ; one of them, 

 however, may possibly be a mere variety of the other. 



The first Cancer angulatus, L. ; Herbst., I, 13; Leach, Ma- 

 lac. Brit., XIII, has the anterior angles of its shell prolonged 

 into a point, and a second, but smaller spine behind. Two 

 others are observed on the claws of the males, one on the joint 

 called the arm, and the other on the internal side of the carpus ; 

 the hands are elongated, and somewhat narrowed at base ; ano- 

 ther tooth is found on the superior extremity of the thighs of the 

 other feet. The body is reddish. It inhabits the western coast 

 of France, and that of England. 



In the second Cancer rhomboides, L., the shell presents no 

 other spines than those formed by the prolongation of the ante- 

 rior angles. The body is smaller, and of a reddish- white or 

 llesh colour. From the rocky localities of the Mediterranean f. 



In the second division of the Quadrilatcra, the fourth joint of the 



mil foot jaws, or those which cover the other parts of the mouth 

 below. U iii>erted in the middle of the extremity of the preceding 

 joint, or more outwardly. 



-ee also the subgenua OCYPODE. I have made a new one called TRICHODAC- 

 i M rs, with a fresh. water species from Brazil, analogous to the preceding ones, 

 hut with :m almost square slull, tin- thinl joint of the rxtrrnal foot -jaws forming an 

 elongated triangle hooked at the mil. ami thrtir-i covrrnl \\itli a dose do\\n. 



The Gratptu tnselatus, of the (.1. (m-v, 2) of Nat. IIM.. l.m-y. Mrth...!.. i- uNo 

 Mi i i v, but one of too littli imjmitauce to be treated of 



,1 in i \\.-ik hkt ' 



article Rhombillr, Encyc. Mcthodiquc. 



