i6o T. R. R. StebbinG: The Fauna of Brackish Ponds. [VOL. I, 



Quadrivisio bengalensis , n.sp. 

 (Plate VII.) 



Head much longer than first segment of peraeon, rostral projec- 

 tion minute, ocular lobes rounded. Second and third side-plates 

 rather deeper than first and fourth, the fourth excavate behind for 

 the anterior margin of the bi-lobed fifth. Postero-lateral angles in 

 the large pleon segments i — 3 produced into a very minute tooth. 

 The fourth and one or two other of the pleon segments carry on the 

 hind margin a widely spaced pair of denticles, very small and difficult 

 to observe. The telson is small, not so long as broad, divided to the 

 base, each lobe having several little spines down the inner margin, 

 and some of those round the apex close-set. 



Eyes dark, placed near the margin of the head, all with numerous 

 lenses, the lateral pair rounded, the dorsal pair crescent-shaped, with 

 the concavity in front. 



First antenncB. — First joint rather stout and long, second much 

 thinner, in male longer than the first, in female subequal to it; 

 third joint small, flagellum nearly as long as peduncle, having in 

 the male more than twenty joints, the long and slender accessory 

 flagellum ten-jointed. 



Second antenncB. — Peduncle very elongate, especially in the 

 male, gland-cone prominent, fifth joint in male considerably longer 

 than the long fourth joint, both slightly curved; in the female 

 the fifth joint straight, not longer than the fourth, the flagellum 

 shorter than the peduncle, attaining the number of 17 joints, which 

 is slightly exceeded in the other sex. 



Mandibles. — Cutting edge six-dentate, accessory plate stronger 

 on the left than on the right mandible, spines of spine row numerous, 

 molar strong, palp slight as in Melita ohtusata (Montagu) and, among 

 the Atylidse, in Nototropis swammerdamei (Milne-Edwards) ; the 

 third joint slightly longer than the second, tipped with two long setae. 



First and second maxillcB. — These show a remarkable resem- 

 blance to those of Ceradocus rubromaculatus (Stimpson), and present 

 the same difficulty in counting the spines on the outer plate of the 

 first pair, which are not fewer than nine, but may be eleven. 



Maxillipeds. — Outer plate not reaching end of palp's long second 

 joint. The third joint of the palp appears to be less elongate in 

 the female than it is in the male. 



First gnatho pods. —"The fifth joint is considerably larger than 

 the sixth, strongly fringed on and near the hind margin with groups 

 of spines planted on the inner surface ; the sixth joint oblong oval, 

 with scale-like spinules along the hind margin, and seven rows of 

 spines on the inner surface adjacent to the front margin, the palm 

 very short transversely rounded, not overlapped by the small finger. 



Second gnathopods. — In the male the fourth joint has the 

 hind margin produced to a sharp apex, the fifth joint distally 

 cup-like, not longer than broad, the sixth longer and much broader 

 than the second, with smooth nearly straight front margin, the hind 

 margin slightly setose and denticulate till it meets the very oblique 



