2i6 Memoirs of the Indian Museum. [Vol. V, 



Two ovigerous females were obtained in the months of March and September 

 in water of specific gravity varying from i-ooo— i-oii. 

 The type specimens are registered under no. 8944/10. 



Tribe BliACHYGNATHA. 



Family HYMENOSOMATIDAE. 



Genus ELAMENA, Milne-Edwards. 



Sub-genus Trigonoplax, Milne-Edwards. 



1853. Trigonoplax, Milne-Edwards, Ann. Set. nat. Zool. {3), XX, p. 224. 

 1900. Trigonoplax, Alcock, Joiirn. Asiat. Soc. Bengal, LXIX, p. 386. 



Elamena (Trigonoplax) cimex, sp. nov. 

 (Plate XII, fig. 3.) 

 The carapace is flat and lamellar and more or less cordiform in shape ; its length, 

 including the front, is a trifle greater than the breadth, the proportion being as 31 

 to 28. The postero-lateral borders show a slight emargination at the base of each 

 of the last two pairs of legs and are only about half as long as the antero-lateral. 

 The regions of the carapace are defined by shallow grooves, the margin is not up- 

 turned, devoid of teeth or tubercles, and except for a few sparse hairs, most notice- 

 able on the hepatic region, the surface is bare (pi. xii, fig. 3). 



The front is produced to form a distinct rostrum ; it is clearly marked ofi' from 

 the general contour of the carapace and, in the angle formed on either side of its 

 base, the eyes along with portions of the eyestalks are visible. Behind the eye there 

 is a blunt tooth. The rostrum is composed of a single flat plate a little longer 

 than broad; its margins are parallel at the base, narrowing anteriorly to a blunt 

 point. 



The antennules are closely juxtaposed at the base ; the interantennular septum 



is wholly missing. The epistome is nearly 

 twice as broad as long. From the an- 

 terior angles of the buccal cavern a sharp 

 ridge runs backwards on either side of the 

 carapace to the bases of the walking legs 

 and the surface between this ridge and the 

 true lateral margin of the carapace behind 

 the eye is deeply concave. The external 

 maxillipedes completely close the buccal 



cavern. The ischium is a trifle longer than 



Fig. 4. — Elamena (Trigonoblax) clmcx, sv>. nov. .-, j 4-1, „ „ /i 4.1 i r 1 ^.i 



^ ^ ^ I' I ' i' the merus and the exopod, though slightly 



Anterior part of carapace of a female, seen from below. 



overlapped at the distal end by the adja- 

 cent margin of the merus, is nevertheless visible, in part, throughout its length 

 (text-fig. 4). 



