pdh.Q 



j)(lh.\3 



arl.S arh.f> plh.\2 arh.\2 p 



ar 



(im 



Fig. 4. — Astacus flnvuttilis.—In A, the gills, exposed by the removal of the branchio- 

 stegite, are seen in their natural position ; inB, the podobranchise (see p. 75) are re- 

 moved, and the anterior set of arthrobranchise turned doAvnwards ( x 2): 1, eye-stalk ; 

 3, antennule ; 3, antenna ; U, mandible : 6, scaphognathite ; 7, first niaxillipede, inB 

 the epipodite. to which the line points, is partly removed ; 8, second niaxillipede : 

 9, third maxillipede ; 10, forceps ; lU, foiirth ambulatory leg ; 15, first abdominal 

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

 the posterior arthrobranchise of the second and third maxillipedes and of the third 

 ambulatory leg ; arb'. 9, arh'. IS, the anterior arthrobranchise of the third maxillipede 

 and of the third ambulatoiy leg ; phd. 8, podobranchise of the second maxillipede ; 

 phd. 13, that of the third ambulatory leg ; -plh. 12, jilb. 13, the two rudimentary 

 pleurobranchiw ; plh. lU, the functional pleurobranchia ; r, rostrum. 



