Species of Amphipoda Gammarina. 345 



Head longer than tlie first two body-segtnents ; eyes indi- 

 cated by a clear almost circular space on the top of the head. 

 Upper antennaj with tlie first joint very large, expanding 

 distally, and completely filling the space between the rostrum 

 and the anterior margin of the head, exceeding in length the 

 next two joints, which are less than half as wide ; the distal 

 margin of the second joint has a sinus on the upperside, from 

 which a scale-like appendage reaches to the end of the upper 

 margin of the third joint, which is much shorter than the 

 lower margin. First joint of flagellum as long as the last 

 two of the peduncle, furred, and provided with long setae on 

 the upperside ; next eight or nine joints very short, setose, 

 tapering gradually into longer and thinner joints, about twenty- 

 eight in all. 



Lower antennge : — Penultimate joint of peduncle reaching 

 to the end of the first joint of the flagellum of the upper 

 antennae, constricted at the proximal end ; last joint longer 

 than the preceding, both with setules along the upper margin ; 

 flagellum very slender, with the third joint longer than the 

 preceding and succeeding joints, about twenty-eight in all. 



First gnathopod : — First joint thicker than any of the 

 following, about as long as the next three ; carpus rather 

 more than half as long as the propodos, which tapers gradually 

 to the base of the dactylus, and has three set£e and six setules 

 on the lower margin ; the dactylus is expanded at the base, 

 not deflexed, and fully half as long as the propodos. Fpi- 

 mere subtriangular. 



Second gnathopod : — Like the first in general form, but the 

 lower margins of the carpus and propodos are furred and 

 densely clothed with set^, which lengthen distally; many of 

 those on the carpus are greatly curved. Epimere rounded- 

 oblong. 



First and second perseopoda :— First joint as long as the 

 third and fourth together, third obcordate, the distal end as 

 wide as the shorter diameter of the broadly oval fourth joint ; 

 fifth joint as long as, but much narrower than the fourth ; 

 dactylus about two thirds the length of the fifth joint ; hind 

 margins of third, fourth, and fifth joints fringed with long 

 seta3, which are most numerous on the fourth. 



Third pergeopoda : — First joint twice as wide and not so long 

 as the third, which is about equal to the fourth and fifth, but 

 twice as wide. Dactylus more than half as long as the 

 propodos. 



Fourth and fifth perseopoda subequal, of the same form as 

 the third, but much longer. 



Branchial vesicles and pleopoda large. 

 Ann. ds Mag. N. Hist. Ser. 6. Vol. xvii. 25 



