PLATE XXVIII. 



Astacopsis spinifer (p. 194). 



The lateral wall of the carapace has been removed to show the branchial arrangement ; 

 podobranchise removed to show the plan of the branchiae beneath ; arthrobranchiae 

 removed from the first two pairs of pereiopoda to show their position and that of 

 the pleurobranchise. 



k. First pair of pereiopoda. 



pdb. Podobranchise. 



arb. Arthrobranchiae. 



plb. Pleurobranchise. 



rat. Movable appendages, probably the rudiments of the foliaceous appendages 

 that form the ventral incubatory pouch in certain genera, 



d. Siagon or mandible ; 1 coxa, 2 basis, 3 terminal joint. 



e. First siagnopod ; 1 coxa, 2 basis, 3 ischium, 4 terminal joint. 



f. Second siagnopod ; 1 coxa, which carries the mastigobranchial plate ; other 



numerals as before. 

 y. Third siagnopod ; numerals as before ; ec, a multiarticulate ecphysis of the 



basis. 



h. First gnathopod ; 1, 2, 3, as before ; 4 meros, 5 carpos, 6 propodos. 



i. Second gnathopod ; numerals as before ; ec, ecphysis ; pdb, podobranchia. 



pdbr. Podobranchia. 



arb. a. Anterior arthrobranchia. , 



> Arranged in a diagrammatic section. 

 arb.p. Posterior arthrobranchia. 



plbr. Pleurobranchia. 



