I. '08. 



110 



pace. The antennal scale (fig. 5) is about two-thirds the 

 length of the carapace, only very slightly narrowed apically, 

 and rather more than one-third as wide as long ; externally it 

 is straight or slightly concave and terminates in a stout tooth 

 which does not reach as far forward as the lamellar portion. 

 The antennal flagellum is about half the entire length of the 

 animal. 



The oral appendages differ from those of Hippolyte varians 

 as follows : — The niandihle (fig. 11) bears a palp composed of 

 three joints and the molar is but little wider than the incisor 

 process ; in the first maxilla (fig. 10) the endopod is longer 

 and the middle lobe or basipodite evenly rounded apically ; the 

 endopod of the second maxilla (fig. 9) is narrowed distally and 

 is not flexed outwards and the distal lobe of the basipodite 

 or protognath is wider than the proximal one. In the first 

 maxillipede (fig. 8) the endopod is more slender than in H. 

 varians , and is only set with a few setae ; the lamellar portion 

 of the exopod is oblong and is not contracted at its base and 

 the epipod consists of two large lobes. In the second 

 maxillipede (fig. 7) the exopod and endopod are longer and 

 more slender, the terminal joint of the latter being very short 

 and extremely wide. A comparison of the figures on plates 

 XVI and XIII will show these and other less important dis- 

 tinctions more clearly than a long description. 



The third maxillipedes reach beyond the antennal scale by 

 nearly the whole of the terminal joint ; the slender exopod is 

 about half the length of the ante-penultimate segment. The 

 first pair of pereiopods reaches slightly beyond the antennal 

 scale ; the merus is longer than the ischium, and the chela 

 and short triangular carpus are rather shorter than the is- 

 chium and merus combined. The chela is very stout, and the 

 dactylus is about two-thirds the length of the palm. In the 

 second- pair the ischium, which is much widened distally, is 

 longer than the merus and about equal in length to the chela. 

 The carpus is scarcely half the length of the merus and is 

 divided into two joints by an oblique articulation ; the chela 

 is very narrow, much less robust than that of the first pair 

 and its dactylus is not much less than twice the length of the 

 palm. The third and fourth pairs of pereiopods are much 

 longer than the first pair, the fifth is still longer. In all, the 

 ischium is slightly shorter than the carpus, while the merus is 

 shorter than the propodus ; the dactyli of the three pairs are 

 quite similar, extremely short and claw-like. 



The branchial formula is : — 





vn. 



VIII. 



IX. 



X. 



XI. 



xn. 



xm. 



1 



XIV. j 



Podobranchiae, 



ep. 



ep. 



ep. 



ep. 



ep. 



ep. 



ep. 



j 



i 



Arthrobranchiae, 



... 



... 





... 







I 



... 



Pleurobraucbiae, 



... 



... 





1 



1 



I 



1 



1 



