I. '08. 



99 



Family HIPPOLYTIDAE. 



In a recent paper (1906) Caiman has given an account of 

 some of the genera of this family, and has supplied a most 

 useful table for their discrimination. All the five^ genera 

 known from British and Irish waters fall under that section 

 of the family which is characterized by the absence of arthro- 

 branchs above the^ bases of the pereiopods. The chief 

 characters of these genera are best shown in tabular form. 



1 



1 



Hippolyte. 

 p. 100. ' 



1 

 Spirontocaris. 



p. 102. 



Caridion. 

 p. 108. 



Leontocaris. \ 

 p. 113. 



BijlhocarH. 

 p. 117. 



Incisor [)rocess 

 of mandible. 



present. 



present. 



present. 



present 



absent. 



Mandibular 

 palp. 



absent. 



present 

 2-jointed. 



preF.ent 

 3-jointed 



present 

 1-jointed. 



absent. 



Supra-orbital 

 spines of carapace. 



present. 



present 



or 

 absent. 



absent. 



absent. 



present. 



Exopod of 

 third maxillipedes. 



present. 



present 



or (rarely) 



absent 



present. 



absent. 



present. 



Epipods of 



maxillipedes and 



pereiopods. 



2 pairs. 



1 4-6 pairs.2 



7 pairs. 



2 pairs. 



1 pair. 



Carpus of 

 second pereiopods. 



3-jointed. 



6-7-jointed. 



2-jointed. 



4-jointed. 



9-10-jointed 



The highly specialized genus Leontocaris may be at once 

 distinguished from the others by the assymmetry of the second 

 pair of pereiopods ; both chelae of this pair are larger than those 

 of the first, that of one side being of enormous size. 



1 Since this was written anotlaer Hippolytid, Cryptocheles jjygviaeai 

 G. O. Sars, has been found within the British area. C. pygmaea is a very 

 scarce deep-water species, and is readily distinguished from all other 

 British Hippolytidae by its unpigmented eyes. It is described and 

 figured by Norman, 1894, p. 271, pi. xii., figs. 2-5. The solitary British 

 specimen was found by the Scotch Fishery Board off the N.W. coast 

 of Scotland; elsewhere it is known only from the coasts of Norway. 



2 In all British and Irish species of Spirontocaris five or six pairs of 

 epipods are present, viz., on the three pairs of maxillipedes and first 

 two or three pairs of pereiopods. 



Q 2 



