PORTUN vUS. 
PORTUNUS. Daid., Fabr., Lam., Bosc, Latr. 
CANCER. Linn., Penn, &c. ‘ 
Antenne extcrne setacex articulis duobus primis majoribus, in oculorum cantho interno imserte. 
Pedipalporum geminorum exiernorum caulis interai articulus secundus ad apicem internum trun- 
catus, aut ad internum latus emarginatus pro insertione palpi triarticulati, elongato- 
subconici. 
Pedum par anticum majus, inequale, didactylum, manibus externe elevato-lineatis ; paria 2, 3, et 
. 4 unguibus elongatis, qradrangulatis, acutis, longitudinaliter sulcatis; par quintum tarsis 
unguibusque foliaceis, natatoriis. , ? 
Abdomen maris 5-articulatum, segmento antepenultimo longiore basi ultrinque abrupte ial 2 
Fenix 7-articulatum, articulo ultimo precedente abrupte angustiore. 
Teste margo anticus arcuatus, semicireularis lateribus (sepius 35-dentatis) sensim postice in 
angulum convergentibus, apiece subtruncato; diametro transverso majore; orbita postice 
externe bifissa, subtus externe unifissa, angulo interno imperfecto aut subimperfecto. 
Oculi pedunculo brevi crassiores. 
GENERIS DIVISIONES. 
* Ungues postici linea longitudinali elgeata. Pedipalpi gemini exrterni caulis interni articulo secundo 
ad apicem internum truncato. : 
a. Orbita interne ad antennarum inseriionem imperfecta ; carpi bidentati. 
b. Ordita interne subimperfecta: carpi unidentati. . 
*=* Ungues postici ecostati. Pedipalpi gemini externi caulis interni articulo secundo ad latus internum 
emarginato. (Orbita interne sub antennarum externarum insertione imperfecta. Carpi, 
unidentati ). . 
External antenne setaceous, with the two first segments largest. inserted at the internal 
corner of the eye. Second joint of the internal footstalk of the external double palpes, with the 
internal apex truncate, or with the internal side notched for the insertion of the elongate-conic 
. palpes, which are composed of three joints. Anterior pair of legs largest, didactyle, and 
unequal in size, the hands with elevated longitudinal lines; the second, third, and fourth pair 
with elongate, acute, four-sided longitudinally grooved claws; the fifth pair with the tarsi and 
claws compressed and formed for swimming. Abdomen or flap of the male five-jointed, the 
middle segment longest with the base on each side abruptly produced; flap of the female seven 
jointed, the last joint abruptly narrower than the sixth. Anterior margin of the shell semicir- 
cular with the sides (armed with five teeth in the indigenous species) gradually converging into 
an angle behind, the apex truncate, the transverse diameter greatest: orbit of the eyes externally 
behind with two fissures, below externally with one fissure, the internal corner more or less 
imperfect. Eyes thicker than their footstalk, which is short. 
