264 



THE CRUSTACEA 



The antennules have the three segments of the peduncle always 

 distinct, and as a rule both flagella are present. In many Caridea 



Fia. 154. 



Ocular peduncles of Decapoda. A, Ranina seabra (Bracliyura). B, Astacus fluviatilis 

 (Astacura). C, PodojMhalimis vigil (Brachyura). D, Macrophthalmus pcctinipes (fiTa.ct\y\\Ta). 1, 

 2, 3, successive segments of the peduncle. 



Pig. 155. 



Ocypoda truwrocera (Brachyura) in a natural attitude with the eyes elevated, showing the 

 styliform prolongation of the ocular peduncles. (From Alcock, Naturalist in Indian Seas.) 



(Fig. 156, A) the outer flagellum is bifurcated near the base, and 

 in some cases the three flagella appear to arise separately from the 



