CHAP. V.] 



HOMCEOSIS IN ARTHROPODA. 



151 



Milne-Edwards, A., Comptes Rendus, lix. 1864, p. 710 ; described 

 and figured by Howes, W. B., Proc. Zool. Soc, 1887, p. 469. 



Fig. 19. Palinurus penicillatus, the left eye bearing an antenna-like flagellum. 

 After Howes. 



Hippolyte fabricii differs from other species of the genus in 

 being usually without epipodites at the bases of all the cephalo- 

 thoracic legs except the first pair, while in the other species these 

 appendages are usually present upon the bases of the first and 

 second, or upon the first, second and third pairs, and on this 

 character it was placed by Kroyer in a separate section of the 

 genus. 



Of 52 individuals (18 males varying in length from 27 mm. to 

 39 mm. and 34 females varying from 16'5 mm. to 50 mm.), from 

 various localities on the New England coast, 47 had the normal 

 number of epipodites, while 5 had epipodites on one or both of the 

 second pairs of legs. Of the latter 3 were from the Bay of Fundy ; 

 one </, 35 mm. long, has well-developed epipodites on each side of 

 the 2nd pair of legs ; another <-f , 36 mm. long, has a short epipodite 

 on the left side and none on the right ; the other, % , 47 mm. lung, 

 has a well-developed epipodite on the left side and none on the 

 right. The two others were from Casco Bay; a $,36 mm. long, 

 with a short epipodite on the left side, and a </, 28 mm. long, with 

 a rudimentary one on the right side. As the measurements shew, 

 the presence of these epipodites is not characteristic of the young. 

 Smith, S. J., Trans. Connecticut Acad., v. 1879, p. 64. 



