HOMARUS AND NEPHROPS. 



259 



fully developed pleurobranchi^e. Moreover, the bran- 

 chial filaments of these gills are much stiffer and more 

 closely set than in most crayfishes. But the most im- 

 portant distinction is presented by the i:)odobranchi{e, in 

 which the stem is, as it were, completely split into two 

 parts longitudinally (as in fig. 68, B) ; one half (ejj) 



C' st 



Fig. 68. Podjbranchi£e of A, Parii.stacus ; B, Nepki'02)s ; C, Palcpmon. 

 A', C, transverse sections of A and C respectively, a, point of attach- 

 ment ; al, wing--like expansion of the stem ; b, base ; hr, branchial 

 filaments ; ep, epipodi'e ; Z, branchial laminge ; ^^Z, plume ; st, stem. 



corresponding with the lamina of the crayfish gill, and the 

 other {pi) with its plume. Hence the base [h) of the 

 podobrancliia bears the gill in front; while, behind, it 

 is continued into a broad epipoditic plate {ep) slightly 

 folded upon itself longitudinally but not plaited, as in the 

 crayfish. 



The Norway Lobster {Xcphrops norvegicas, fig. 69) 



