188 CRUSTACEA. 



in both sexes ; the shell ovoid, widely truncated, without any projec- 

 tion like a rostrum, and flattened. 



As remarked by Desmarest, we may observe on each side and 

 above the origin of the claws, an oblique fissure resembling a button- 

 hole, longitudinally intersected by a diaphragm, ciliated, like itself, 

 on the margin that communicates with the branchiae, and affording 

 an issue to the water that bathes them. 



Three species are found in the Mediterranean* ; the others 



inhabit Oriental seas, and one of them D. quadridens, Fabr., 



Herbst., X, 70, is also obtained there in a fossil state. 



There, the shell is sometimes nearly orbicular, or globular, and 



sometimes arcuated anteriorly and narrowed posteriorly, and dentated 



or spinous on the sides. The eyes are situated near the middle of the 



front, and placed on short pedicles. 



Dromia, Fab. 



The four posterior feet inserted in the back, and terminated by a 

 double hook ; the shell suborbicular or nearly globular, convex and 

 woolly, or very hairy. 



"With their hind feet they seize upon Alcyonii, shells, and other 

 bodies, beneath which they shelter themselves, transporting them 

 wherever they go. 



The most common species,' — Cancer doiniia, L. Rumph., 

 ^lus., XI, ] ; Herbst., XVIIl, 103, is found in every sea, that of 

 the North excepted, It is covered with a brown down, and has 

 five teeth on each lateral margin and three in front. The fingers 

 are stout, deeply dentated on the two edges, and partly rose- 

 coloured. Some authors say that it is venomous. 



The Death's Head, — Cancer capiU moriuum, L. ; Dormia 

 cli/peata, Act. Hafn., 1802, is smaller, more convex, almost 

 glubular, with three teeth on each side in its anterior margin, 

 and has a short front, emarginate in the middle and laterally 

 sinuous. It is found on the coast of Barbary f . 



Dynomene, Lat. 



The two posterior feet much smaller than the others, alone dorsal, 

 and apparently unarmed ; the shell widened, and nearly resembling 

 a reversed heart tnmcated j'osteriorly, like that of the last Quadri- 

 latera, and simply pubescent. The ocular pedicles are longer than 

 those of the Dromise. 



But a single species, the Di/nomene liispide, Desmar., Consid., 

 XVIII, 2, is known ; it is found at the Isle of France. 



The last Notopoda differ from the preceding in the feet, all of 

 which except the claws, terminate in a fin, and from all the Brachy- 

 ura in the extension of their tail. Such is the 



* Durippe lanata ; Cancer lanafus, L. ; Desmar., Consider., XVII, 2; — D. 

 affinis, Id.; Herbst,, XI, 67; — Cancer mascarone, Herbst., XI, 68. 



-|- For the other species see Desmar., Consul, Gen. sur hi Classe des Crust., 

 p. 136, et seq. 



