POCKETED PAEASITES 405 



LeponiscMs, Giard, has the single species Leponiscus 

 pollicvpedis, parasitic, as the name indicates, on a pedun- 

 culate Cirripede. 



Family 6. --TSntoniscidoi. 



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 antennas are 

 metamorphosed into lips ; the labrum, hypostome and 

 mandibles forming the oral apparatus. The maxillipeds 

 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 tbe 

 fifth pair of feet, and by their prolongations determining 

 the shape of the perseon ; 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 person 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 

 Entoniscidae in connection with their hosts. 



Portunion (^Portunus) 



Entione (AeJuam') 



Cancrion (Cancer') 



Grapsion (^Grapms) 

 Entoniscus (PwceHama) 



