DEC A POD A. 



ANOMOURA. 



rORCELLANAD^E. 



GENUS PORCELLANA, LAM. 



CANCER. 

 PORCELLANA. 

 PORCBLLANA PlSIDIA. 



Lin. Herbst. Pennant. 

 Lamarck, Edwards. 

 Leach, Desmarest. 



Generic Character. External antennae inserted at the outer 

 side of the eyes; the basal portion formed of three joints, of which 

 the second is the largest and the longest ; the terminal portion very 

 long, setaceous. Internal antennce concealed beneath the front, 

 very small. External pedipalps greatly developed ; the second 

 joint very large, rounded, with a single tooth on the outer anterior 

 angle ; the third joint much smaller, irregularly trigonal, and with 

 the remaining joints fringed with long hair at the edges. Anterior 

 feet very large, and more or less flattened ; the arm very short ; 

 the wrist long and dilated on the upper and inner edge, so as to 

 form a hollow space, in which the hand lies when retracted ; the 

 hand narrow at its base, becoming very broad forwards ; the 

 fingers strong and scarcely toothed. Second, third, and fourth 

 pairs of feet ambulatory, nearly cylindrical ; fifth pair very small, 

 didactyle, and doubled together at the latero-posterior angle of the 

 carapace. Carapace suborbicular, depressed. Eyes small, lodged 

 in an orbit, the parieties of which are imperfect, excepting above. 

 Abdomen very large, much developed, nearly as long as the cara- 

 pace, ordinarily closed against the sternum, composed of seven 

 distinct segments, and terminating in a broad fan-like tail, formed, 

 as in the MACROURA, of the terminal segment of the abdomen and 

 the appendices of the penultimate. 



IN this genus we find a marked approach to the Ma- 

 crourous group in the development of the pedipalps and 

 of the tail, as well as in several other less obvious charac- 





