PILUMNUS. 
CANCER. LinnS, Pennant. 
PILUMNUS. Leach. 
Antenna externa setace®, subelongatae, graciles, ad oculorum canthum internum inserts; : 
internee in foveolis transverso-subobliquis reponendae. 
Peclipalpi gernini externi caulis interioris articulo secundo sub transverso-quadrato, ad apicem 
internum emarginato, palpigero. 
Pedum par anticum valde ina?quale, didactylum ; digitis dentatis ; paria alia ambulatoria ; 
ungues apice acuti, nudi. 
Abdomen in utroque sexu 7-articulatum. 
Testa transversa, postice truncata, margine antico in lineam scmiellipticam arcuato. 
Oculi pedunculo brevi haud crassiores. 
External antenna; setaceous, subelongate, inserted at the internal angle of the eyes ; internal 
antenna; placed in transverse somewhat oblique excavations. External double pedipalpes with 
the second joint of their internal footstalk, having its internal apex notched for the insertion of 
the palpi. Anterior pair of legs very unequal, didactyle; the fingers toothed; other pairs 
formed for walking; claws with their extremities sharp and naked. Abdomen in both sexes 
seven-jointed. Shell transverse, the anterior margin semielliptically bent, hinder margin trun- 
cate. Eyes not thicker than their peduncles, which are short. 
The animals of this Genus live in holes of rocks and under stones in the sea. Their motion is 
slow, and all the species that I have seen are more or less covered with bristlv hairs, which are 
most obvious on their legs. 
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