165 



than the others. The first four pairs carry cpipodites which may be of good 

 length or may merely be membranous expansions of the base of the podo- 

 branchiae. 



The abdominal appendages behind the first pair are biramous, with the 

 rami narrowly foliaceous, and with an internal appendix at the base of the 

 endopodite. The 1st pair are uniramous and in the male have the form of a 

 slender scoop. In the male also the 2nd pair have an additional internal 

 appendix. 



Synopsis of the genera of Eryonidse of tin' Imlian Necton and Benthos. 



I. Eyestalks immovably impacted in deep sinuses of tlie anterior border of the 

 carapace : the fixed finger of the large chelipeds without any enlarged 

 tooth : 



i. Carapace depressed, with sharply denned lateral borders : inner 

 antennular flagellum longer than the carapace: 



1. The epipodite of the external maxillipeds is a mere papilla; 



those of the thoracic legs are merely membranous 



expansions of ihe base of their podobranchiw ... POLYCHBLES. 



2. The epipodite of the external maxillipeds is of fair size ; 



those of the thoracic legs are normal epipodites ascend- 

 ing into the branchial chamber ... ... ... PBNTACHELES. 



ii. Carapace inflated, globose,, longer than the abdomen: inner 



antennular flagellum much shorter than the carapace ... EBTONICOS. 



II. Eyestalks immovably fixed beneath and parallel with the anterior border of 

 the carapace : the fixed finger of the large chelipeds with a large spiniform 

 tooth near its distal end : carapace depressed, with sharply defined lateral 

 borders : inner antennular flagellum nearly as long as the body: external 

 maxillipeds and first pair of thoracic legs with long epipodites ... WILLEMOESU. 



There seems to be some little doubt as to the right nomenclature of the 

 various species of this group. 



The Poli/i-l/L-lt.'x described and figured by Heller (1862 > has orbital sinuses 

 and has no epipodite to the external maxillipeds : in this Memoir, therefore, the 

 name Polycheles is applied to the species thus characterized, in which also the 

 epipodites of the thoracic legs are merely membranous expansions of the bases 

 of the podobranchiaa. 



The genus Fentaclides of Spence Bate (1878) is by its author characterized 

 by the form of the last pair of thoracic legs, which are " more or less perfectly 

 chelate in both sexes." But it is characteristic of the family as a whole for the 

 male Willemcesia is, as far as I know, the only exception to have the last 

 pair of legs less perfectly chelate than the female, and on this account recent 

 authors have refused to recognize J!V/^r/(77(,s as a distinct genus. In some of 

 the species allotted to this genus by Speuce Bate, however, the external maxilli- 



