I. '08. 35 



have on some occasions been taken at the surface ; the young 

 stages seem to be confined to the upper strata of the water. 

 The species has been caught over soundings of 139 and 2,516 

 fathoms (Smith), but although frequently taken by the trawl, 

 there is no certain record that it has ever occurred actually on 

 the bottom. 



Tribe CARIDEA. 



This tribe comprises the vast majority of the species of De- 

 capoda Natantia found iri British and Irish waters. Ten 

 families are represented, one of which (Bresiliidae) was estab- 

 lished for the reception of a single species, which has, so far, 

 been found only in the deep water of the Irish Atlantic slope. 



A. Exopods on at least first four pairs of pereiopods. 



I. Pereiopods not enormously long and not all 

 slender, all five pairs with long exo- 

 pods. 



A. Exopods of second maxillipedes absent or 



rudimentary ; first two pereiopods 

 much longer and stouter than re- 

 maining three, . . 'Pasiphaeidae (p. 36). 



B. Exopods of second maxillipedes well de- 



veloped, but without terminal lash ; 

 first two pereiopods not longer or 

 materially stouter than remaining 

 three, . . . Hoplophoridae (p. 55). 



II. Pereiopods very slender and of enormous 

 length, especially the three posterior 

 pairs ; small exopods on the first four 

 pairs only ; exopods of second maxilli- 

 pedes with terminal lash, Nematocarcinidae (p. 75) 



B. Pereiopods with only two exopods on the first 



tw^o pairs, . . . Bresilidae (p. 82). 



C. Exopods usually entirely absent from pereio- 



pods, when present on the first pair 

 only. 



I. Carpus of second pereiopods divided into 

 two or more segments. 



A. Eyes not covered by a projection of 

 frontal margin of carapace. 



i. First pereiopods both simple or both 

 chelate ; rostrum usually of consider- 

 . able size and armed with spines. 



c 2 



