248 THE COMPARATIVE MORPHOLOGY OF THE CRAYFISH. 



extent than those do from one another. The gills are, 

 in fact, reduced to seventeen on each side, in consequence 



Fig. 63. Cambarus Clarkli, male (J nat. size), after Ilagen. 

 of the ahsenc^c^Jh^ph^ro^branchia of the last thoracic, 

 somite; and there are some other differences to which 

 it is not needful to refer at present. It is convenient to 



