DKCAPODA. 171 



Two naturalists, travellers of the government, prematurely taken 

 from the sciences, Delande and Leschenault-de-Latour, discovered 

 two other species ; one was collected by the first in his travels to 

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

 Ceylon. 



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

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

 Indies. 



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

 X, ii, is proportionably wider and flatter than the others, pre- 

 senting certain characters which seem to indicate a particular 

 division *. 



Other Quadrilatera having, like the preceding ones, the fourth 

 joint of the 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. The 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 vai'iety 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 

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



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

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

 below, is inserted in the middle of the extremity of the preceding 

 joint, or more outwardly. 



* See also the subgenus Ocypode. I have made a new one called Trichodac- 

 lYLUS, with a fresh-water species from Brazil, analogous to the preceding ones, 

 but with an almost square shell, the third joint of the external foot-jaws forming an 

 elongated triangle hooked at the end, and the tarsi covered with a close down. 



The Graspus fcssclatiis, of the pi. (cccv, 2) of Nat. Hist., Encyc. Method., is also 

 the type of the new genus Melia, but one of too little importance to be treated of 

 in detail in a work like this. 



t See the article RhomUUr, Encyc. Methodique. 



