CORYSTES. 
CORYSTES. Latreilie, Leach, Lamarck. 
ALBUNEA. Fabdricii, Bosc. 
CANCER. Pennant, Herbst. 
Antenne extcriores corpore longiores, setacew, utrinque ciliate ; segmento tertio ex articulis 
elongatis, cylindricis efformato. 
Pedipalpi gemini externi caulis interni articulo secundo (primo longiore) augusto, apice angus- 
tiore rotundato, latere interno laté emarginato. 
Pedes decem: par anticum majus equale, didactylum, digitis deflexis; Maris corpore duplo 
longius, subcylindricum, manu gradatim subcrassiore, subcompressé ; FEMINE corporis 
longitudine manu compressa: paria reliqua tibiis tarsisque longitudine subequalibus, 
unguibus elongatis, rectis, acutis, longitudinalitér sulcatis instructa. 
Abdomen Maris 5-articulatum ; articulo primo transyerso-linéari ; secundo longiore utrinque 
posticé producto ; tertio wxqualitér subquadrato; quarto precedente angustiore, 
transverso ; quinto angustiore, subtriangulari apice rotundato : 
FEMIN# 7-articulatum ; articulis sex primis transversis anticé arcuatis ; septimo trian- 
gulari, apice rotundato. 
Testa oblongo-ovata anticé subrostrata, posticé truncata, marginata: orbita superné fissura una. 
Oculi pedunculo reclivi haud crassiores. 
Exterior antenné longer than the body, setaceous, ciliated on each side: the third segment 
composed of elongate, cylindric joints. Eternal double féetpalpes, with the second joint of the 
internal footstalk (longer than the first), narrow, its point more slender and rounded ; its internal 
side broadly notched. Zegs ten: anterior pair largest, unequal, didactyle, with deflexed fingers ; 
of the mate double the length of the body, subcylindric ; the hand gradually somewhat thicker, 
and subcompressed : of the remAxe the length of the body; hand compressed : other legs with 
the tibiz and tarsi of subequal length: claws elongate, straight, sharp, longitudinally sulcated. 
Abdomen of the mare five-jointed: first joint transverse-linear; second longer, produced on 
each side behind; third equally subquadrate; fourth narrower than the third, transverse; fifth 
narrower, subtriangular ; the apex rounded: of the FEMALE seven-jointed; six first joints 
transverse anteriorly arcuated; seventh triangular, its apex rounded. Shell oblong-ovate, 
anteriorly subrostrated, behind truncate, margined: orbit above with one fissure. Eyes not 
thicker than their peduncles, which bend backward. 
One species only of this genus, has hitherto been noticed by naturalists, and of its economy 
and mode of life nothing is known. 
