n6 COMPARATIVE ANATOMY 



resemble modified limbs, and are reckoned as such by some 



B 



25 



A. Ventral view of the male, and B, ventral view of the female 

 crayfish. The thoracic limbs of one side are removed, as also 

 the ova from the right side of the abdomen of the female. /, 

 the first antennae; //, the second antennae ; VII, the second 

 maxillipeds ; VIII, the third maxillipeds ; IX, the chelae; 

 * X-XIII, the four pairs of pareiopods ; XIV-XIX, the six ab- 

 dominal segments with their appendages; T, the telson ; ^ 



male generative aperture ; Q female generative aperture ; 



an, anus ; ex, opening of the green gland on the basal joint of 

 the second antennas; r, rudimentary first abdominal limb of 

 the female ; st, sternum ; ov, ova, carried on the abdominal 

 limbs of the female ; ex.p, exopodite, and en.p, endopodite of the 

 last pair of abdominal limbs. 



authors, including Huxley. But we shall not adopt this view, 



