pdh.s 



-pdh.\3 



arl.Q arb.<)j>lh\2 mi 13 pll^^ 



Fig. 4:.— Astams fluviatilis.— In A, the gills, exposed by the removal of the branchio- 

 stegite, are seen in their natural position ; inB, the ]iodobranchite (sec p. 75) are re- 

 moved, and the anterior set of arthrobranohise turned downwards (x 2): J, eye-stalk ; 

 S, antennule ; S, antenna ; /,, mandible ; 6, scaphognathite ; 7, first maxillipede, in B 

 the epipodite, to which the line iioints, is partly removed ; S, second maxillipede ; 

 9, third maxillii>ede ; 10, forceps ; U, fourth ambulatory leg ; 15, first abdominal 

 appendage; xv., first, and xvi., second abdoininal somite; arh. 8, arb. 9, arb. 13, 

 the posterior arthrobranehia" of the second and third niaxillipedes and of the third 

 ambulatory leg ; arb'. 9, arb'. 13, the anterior arthrobraiiehife of the third maxillipede 

 and of the third ambulatory leg ; pbd. 8, podobranchia- of the second nnixillipede ; 

 pbd. 13, that of the third ambulatory leg ; plb. 12, plb. 13, the two rudimentary 

 pleurobranchisK ; plb. Ih, the {unctional pleurobranchia ; r, rostrum. 



