1878.J 



AND DISTRIBUTION OF THE CRAYFISHES. 



75; 



Asfacus fluviatilis. 



I. The outer face of the podobranehia of the antepenultimate thoracic limb of the 

 left side ( X 4) : B, the basal portion ; si; the stem ; /, the lamina; br, the 

 branchial filaments ; a p, the apical plume. II. The inner face of the same 

 podobranehia ( X 4) : the letters as before, except g, the decurrent fringe, 

 continued from the inner lobe of the lamina. III. A transverse section 

 of the podobranehia, taken a little above the level of h in II. ( X 4) : a, the 

 inner lobe of the lamina ; h, its outer lobe ; st, the stem ; br, the branchial 

 filaments. IV. One of the hooks of the lamina; and V The extremity 

 of one of the setse of the base of the podobranehia : the vertical line indi- 

 cates the scale to which these figures are drawn, and represents jic of an 

 inch. VI. The coxopoditic set.se of the same limb ( X 4). VII. The free 

 end of one of these seta;, magnified to the same degree as IV. and V. 



Proc. Zool. Soc— 1878, No. L. 50 



