1. '08. 135 



of Aegeon ; the four species of group 2, to which sculptus may 

 certainly be added, must therefore be referred to Cheraphilus , 

 or rather to Philochera*s, a name proposed by Stebbing (1900) 

 to replace Cheraphilus , which at its institution by Kinahan 

 contained spinosms, the type species of Pontophilus. 



The deep water form hacazei is now the only British and 

 Irish species which can correctly be assigned to Aegeon, and 

 the capture of Milne-Edwards' Jacqueti involves the inclusion 

 of Sclerocrangon among our native genera of Crangonidae. 

 Norman's solitary record of Sahinea brings the total number 

 up to six, which may be separated thus : — 



I. Second pereiopods chelate. 



A . First pereiopods without an exopod ; endopod of 



last four pairs of pleopods much less than 

 half the length of the exopod, divided into 

 two segments and without an appendix in- 

 terna at the base. 



i. Lateral process of antennules acutely pointed 



distally ; second pereiopods with dactylus less 



than half the length of the propodus. 



a. Carapace without strong sculpture ; an ar- 



throbranch usually present at base of third 



maxillipedes, . . . Crangon (p. 136). 



h. Carapace with very strong sculpture; no 

 arthrobranch at base of third maxillipedes, 



Sclerocrangon (p. 139). 



ii. Lateral process of antennules distally truncate 

 or rounded ; second pereiopods with dactylus 

 much more than half the length of the pro- 

 podus, .... Philocheras (p. 143). 



B. First pereiopods with (or without^) an exopod ; 



endopod of last four pairs of pleopods nearly 

 as long as exopod, composed of a single seg- 

 ment and with an appendix interna at the 

 base, 

 i. Second pereiopods reaching at least to distal 

 extremity of carpus of first pair ; inferior 

 apices of branchiae turned forwards, an ar- 

 throbranch at base of third maxillipedes, 



Aegeon (p. 155). 



ii. Second pereiopods at most not reaching beyond 

 distal extremity of merus of first pair, usually 

 much shorter ; inferior apices of branchiae 

 turned backwards, no arthrobranch at base 

 of third maxillipedes, . . Pontophilus (p. 159). 



II. Second pereiopods simple, not chelate, . . Sahinea, 

 1 This exopod is present. in all the known British species. 



