Species of SunamphithoS. 117 



ceedingly long, as in the adult male, while in the young ones 

 it is exceedingly short. The articulations are coloured alter- 

 nately white and brown. 



The eyes of 8. hamulus are said to be black, those of S. 

 eonformata white with a red spot in the middle. The eyes of 

 my specimens, both male and female, are red. 



The first gnathopods have the wrist for its distal half and 

 the hand parallel-sided. The hand is longer than the wrist, 

 with a straight palm, forming a right angle with the margin. 

 The finger is stout, projecting beyond the palm, and terminating 

 in a nail. In the female the wrist is perhaps a little more 

 triangular than in the male. 



The second gnathopods in the male have a short cup-shaped 

 wrist continuous with the hand, which is large, long-ovate, 

 tapering ; its palm very oblique, waved, having two lobes, 

 which are partially obscured when the long, slightly waved, and 

 much-curved finger is doubled closely against them. In this 

 position the point of the finger overlaps the hand on the inner 

 side. 



In the first two pairs of pereiopoda the meros is much 

 dilated and produced distally into a lobe, which overlaps the 

 carpus ; the third pair are considerably shorter than the two 

 following pairs, the fifth being slightly longer than the fourth. 

 These three pairs have spines along the anterior of the hand. 



The posterior pair of pleopoda have the inner ramus folia- 

 ceous, and the outer terminating in two powerful hooks. Un- 

 fortunately, in the ' British Sessile-eyed Crustacea,' the inner 

 ramus is figured as the outer — no doubt by one of those accidents 

 which, in small figures of minute parts, it is almost impossible 

 to avoid. A character of the outer ramus, conspicuous under 

 the microscope, is not noticed either in the above-mentioned 

 work or in the British-Museum Catalogue of Amphipodous 

 Crustacea — namely, that the upper edge is set with a row of 

 small spines pointing towards the head and looking like a fine 

 saw. The two preceding pairs of caudal appendages are 

 strongly spined. The telson with its hook is very short, and 

 often balks the observer by its aptitude for hiding between the 

 stems of the pleopoda. 



EXPLANATION OF PLATES XI. & XII. 



Fig. 1. Amphithoe cunicidus. 1 a. Head and antenna?. 1 b. Front view 

 of head, showing the insertion of the antenna?. 1 c. First and 

 second gnathopods, much enlarged. 1 d. Second gnathopod, 

 another specimen, much enlarged. 1 e. Telson and caudal 

 appendages, seen from above. 



Fig. 2. First and second gnathopods of Amphithoe ri/brirafa. 2 a. Telson 

 and posterior pleopoda of another specimen, seen from above. 



