70 G- O. Sars. 



The adult male is somewhat smaller than the female, 

 and exhibits the same difference from it as that observed 

 in B. iriarticulata, being on the whole of much more slender 

 form and having the last segment of the anterior division 

 quite simple, without any lateral expansions. Moreover, the 

 tail appears more elongated, and is divided into 5 well- 

 defined segments, besides the caudal lamellæ. 



The right prehensile anterior antenna (fig. 3) is con- 

 structed in a similar manner to that in the male of B. triarticu- 

 lata, the movable terminal part being without any processes 

 or spines and somewhat shorter than the adjoining tumefied 

 part of the antennæ. 



The last pair of legs (fig. 4), as in the other species of 

 the genus, are transformed into strong grasping organs, both 

 legs being nearly equally developed, and each terminating 

 with a slender claw. In the right leg, the outer ramus is 

 distinctly biarticulate and comparatively more strongly deve- 

 loped than in the left leg, where it is composed of a single 

 joint only. In the right leg, moreover, the claw is more 

 abruptly curved than in the left, the claw of which, on 

 the other hand, is more elongated and exhibits outside, 

 near the base, a small secondary spine. The inner ramus 

 of the right leg is simple and conically tapering in its outer 

 part, and carries at the base inside a small, curved bristle; 

 that of the left leg is extremely small, knob-like, and 

 attached to the inside of a projecting corner of the last 

 joint of the basal part. Of the serrated lamella occurring 

 in B. triarticulata inside this joint, no trace is found in 

 the present species. 



Occurrence. — Some specimens of this pretty species 

 were found in a sample taken by Mr. Whitelegge from some 

 pools near Sydney. It is most probable, that the species 



