CORYSTES. 
CORYSTES. Latreille , Leach , Lamarck . 
ALBUNEA. Fabricii , l?o$c. 
CANCER. Pennant , Herbst. 
Antenna; exteriores corpore longiorcs, setacea?, utrinque ciliata? ; segmento tertio ex articulis 
elongatis, cylindricis efformato. 
Pcdipalpi gemini extend caulis interni articulo secundo (primo longiore) augusto, apice *ngus- 
liore rotundato, latere interno late emarginato. 
Pedes decan: par anticum majus a? quale, didactyl uni, digitis deflexis ; maris corpore duplo 
longius, subcylindricum, maim gradatim suberassiore, subcompressa : femin.® corporis 
longitudine manu compressa: paria reliqua tibiis tarsisque longitudine subajqualibus, 
unguibus elongatis, rectis, acutis, longitudinaliter sulcatis instructa. 
Abdomen maris 5-articulatum ; articulo primo transverso-lineari ; secundo longiore utrinque 
postice produeto ; tertio aequaliter subquadrato ; quarto praecedente angustiore, 
transverso ; quinto angustiore, subtriangulari apice roturidato : 
FEMINA3 7-articulatum ; articulis sex primis transversis antice arcuatis ; septimo trian- 
gulari, apice rotundato. 
Testa oblongo-ovata antice subrostrata, postice truncata, marginata : orbit a superne lissura una. 
Oculi pedunculo reclivi haud crassiores. 
Exterior antenna; longer than the body, seiaceous, ciliated ou each side : the third segment 
composed of elongate, cylindric joints. External doable feetpalpes, with the second joint of the 
internal footstalk (longer than the first), narrow, its point more slender and rounded ; its internal 
side broadly notched. Legs ten : anterior pair largest, unequal, didactyle, with deflexed fingers; 
of the male double the length of the body, subcylindric ; the hand gradually somewhat thicker, 
and subcompressed : of the female the length of the body ; hand compressed : other legs with 
the tibia? and tarsi of subequal length : claws elongate, straight, sharp, longitudinally sulcated. 
Abdomen of the male 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. 
