220 Mr. C. Spence Bate on Synaxes. 



XIX. — On Synaxes, a new Genus of Crustacea. 

 By C. Spence Bate, F.R.S. &c. 



[Plate XIV.] 



Genus Synaxes*. 



Carapace anteriorly produced between the eyes to a flat- 

 pointed rostrum. Eyes lodged in distinct orbits. First pair 

 of antenna3 situated beneath the second, slender, terminating 

 in two short flagella ; second situated outside and above the 

 first pair, and terminating in a long and rigid flagellum, 

 having the first two joints of the peduncle fused with the 

 cephalon, and only three joints free. Pereiopoda monodactyle, 

 first pair largest, posterior pair smallest, not chelate in the female. 

 Branchise are trichobranchiate, having the podobranchial 

 plumes attached to long mastibranchial plates (flabella). 

 Pleopoda attached to the first somite of the pleon small and 

 single-branched; those attached to the others are biramose, 

 having the inner branch three-jointed and cylindrical, the 

 outer foliaceous. The rMjpidwra (tail-fan) is broad and 

 foliaceous, anterior portion of each plate calcareous, the pos- 

 terior part membranous. 



Synaxes hyhridica. 



The carapace is slightly depressed. The anterior margin is 

 produced to a rostral point in the dorsal median line, and on 

 the outer side of the eyes to nearly as far as the rostral point, 

 forming a decided orbit in which the eyes are situated. 



The pleon is as broad as the carapace ; and small alee on the 

 first somite laterally protrude and overlap the posterior margin 

 of the carapace laterally. 



A slight but continuous line of elevation or carina traverses 

 the median line of the second and three following somites, but 

 is wanting on the first and sixth. The coxal plates are per- 

 fectly fused with their respective somites, and the rhi^ndura 

 is foliaceous and well developed. 



The eyes are small, placed on short peduncles^ and distant. 



The first pair of antennge have the peduncle long and the 

 flagella short ; the second pair of antennae have only three free 

 joints to the peduncle, and no scajjhocerite (or free scale), the 

 two basal joints being closely fused with the metopus (or 

 face) ; and i\\Q phymacerite (or tubercular opening to the green 

 gland) is situated laterally, at the side of and close to the oral 

 aperture. 



* avvd^is, couibiuation. 



