POCKETED PARASITES 405 



Leponiscus, Giard, has tlie single species Leponiscus 

 IDollicipedis^ parasitic, as the name indicates, on a pedun- 

 culate Cirripede. 



Family 6. -■Entoniscidce. 



The animals are parasitic (to appearance) within the 

 bodies of Brachyura, entering through the branchial into 

 the visceral cavity. In the females the body is extremely 

 unsymmetrical, with traces of segmentation when young ; 

 the head is swollen into a double sphere, the antennae are 

 metamorphosed into li]3s ; the labrum, hypostome and 

 mandibles forming the oral apparatus. The maxiDipeds 

 are lamellar, the feet rudimentary, the marsupium formed 

 of five pairs of plates, with the first pair situated be- 

 tween the rest ; the ovaries opening at the base of the 

 fifth pair of feet, and by their prolongations determining 

 the shape of the pera?on ; the pleon has six segments, fur- 

 nished with lamellar or sabre-shaped pleopods. In the 

 minute male there are two rudimentary eyes, the antennae 

 are evanescent, the maxillipeds are rudimentary, the 

 seventh segment of the peraeon is without appendages ; 

 the six segments of the pleon are without pleopods. The 

 embryo has two eyes, sometimes a nauplian eye, the 

 second antennte elongate, six pairs of feet, five pairs of 

 pleopods and even a pair of uropods. In the 'Crypto- 

 niscian stage ' there are seven pairs of feet. MM. Giard 

 and Bonnier give a provisional genealogical tree of the 

 Entoniscida3 in connection with their hosts. 



Portunion (Fortuoms) 



Entione (Aehisus) 

 Cancrion (Cancer) 



Grapsion (Grajwis) 

 E ntoniscua^ Porcellana) 



