464 6. 0. SARS, [t. XIII 



Specific Characteristics. — Body rather stout, with the anterior division 

 in female ovoid in form, in male oblong oval. Carapace large and deep, with 

 the sides quite smooth, branchial regions somewhat swollen, and slightly 

 gibbous posteriorly; pseudo-rostral projection comparatively short, antero- 

 lateral corners rather projecting. First free segment of mesosome very 

 narrow, band-like; 2nd with 2 juxtaposed rounded dorsal projections; the 

 3 posterior segments keeled dorsally, the keel being elevated to compressed, 

 erect projections, the 2 posterior of which are very prominent and narrowly 

 linguiform in shape. Segments of metasome with 2 longitudinal crests 

 dorsally. Eye well developed, with all 3 corneae distinct in both sexes. Second 

 pair of legs in male much larger than in female, and having the terminal 

 joint armed with 5 recurved hooks. Uropoda rather slender, exceeding half 

 the length of the metasome, rami shorter than the scape, the inner one 

 mucroniform, having in female only a single small spinule in the middle of 

 the inner edge, in male a dense series of ciliated spines occupying the 

 proximal half of that edge. Telson quadrangular. Length of adult female 

 8 mm, of male 9 mm. 



Remarks. — The present very distinct species has recently been detected 

 by Mr. Sowinsky in the Sea of Azow, and is briefly characterised by that 

 naturalist in a russian paper treating of the results of Dr. Ostroumow's 

 dredgings in that part of the Black Sea. Through the kindness of the said 

 author, I have had an opportunity of comparing his original drawings with 

 those made by myself, and have thus convinced myself of the identity of 

 the Caspian form here described with Mr. Sowinsky's species. It is easily 

 distinguishable from the 2 previously known species by its much larger 

 size, and especially by the peculiar armature of the mesosome. 



Description of the female. 



(Pi. i). 



The length of adult ovigerous specimens is about 8 mm, measured from 

 the tip of the pseudo-rostral projection to the end of the uropoda, and the 

 present form thus attains more than twice the size of the 2 previously known 

 species, none of which exceeds 3% mm in length. 



The general form of the body (see figs 1 & 2) is rather robust, with the 

 2 chief divisions of the body sharply marked off from each other. The anterior 

 division, comprising the cephalon and mesosome, is of an ovoid form and about 

 the length of the metasome, excluding the uropoda. When seen from above 

 (fig. 1), it has its greatest breadth, — which somewhat exceeds the height, 

 — across the 2nd free segment of the mesosome, whence it gradually tapers 



Bulletin N. S. IV (XXXVI) p. 300. 



