372 



semblance to another apparently widely remote genus, viz., that of PorHo- 

 2)oreia, and in some species, indeed, the similarity is truly perplexing; but 

 the gnathopoda are very different. In many particulars the new genus would 

 seem to approach nearer to the genus Gammarus than to that of Niphargus, 

 and there are, as above stated, some species of tlie former genus, wliich 

 form, as it were, a transition to tiie type revealed in the present genus. 



In the collection of Mr. Warpachowsky, no less than 4 distinct species 

 of this genus are to be found, one of which will be described below, the others 

 in a subsequent article. A 5th species is also represented in the collection 

 of Dr. Grimm. 



17. Niphargoides caspius (Grimm). 

 (PI. XVI). 



Syu.: Nipliargus caspius, Grimm. 



Specific Characters. — Body somewhat elongated, but very tumid, 

 with Ijroadly vaulted back. Cephalon rathei- small, with the lateral lobes 

 somewhat projecting and rounded at the tip. Anterior pairs of coxal plates 

 but little deeper tlian the corresponding segments, and very densely clothed 

 on their distal edge with slender bristles; 1st pair not expanded distally; 

 4tli pair somewhat deeper than they are broad. Epimeral plates of meta- 

 some well developed, the last 2 pairs nearly rectangular, and having outside 

 the lateral corners an oblique row of delicate bristles. Urosome smooth 

 above. Eyes of moderate size and oval reniform, pigment dark. Antennae 

 rather densely setiferous, the superior ones about twice as long as the 

 cepluilou, and having the 1st joint of the peduncle very large and massive, 

 3rd joint extremely small, flagelliim about the length of the last 2 ped- 

 uncular joints combined, accessory appendage half the length of the flagel- 

 lum and 3-articulate. Inferior antennae with the flagellum extremely short, 

 being scarcely longer than the last peduncular joint. Gnathopoda very un- 

 equal, the posterior ones being much larger than the anterior, propodos in 

 both pairs couically tapering distally, with the palm very oblique, its defi- 

 ning angle being nearly obsolete. Pereiopoda densely setiferous, the 2 ante- 

 I'ior pairs rather robust, the 3 posteiior pairs more slender; basal joint of 

 antepenultimate pair rather narrow and nearly of same shape as that of the 

 penultimate pair; basal joint of last pair moderately expanded and of broadly 

 oval form, being densely fringed with bristles both anteriorly and posteriorly. 

 The 2 anterioi' pairs of uropoda with the rami rather stout and armed with 

 unusually strong, blunt spines; last pair comparatively short, with the outer 

 ramus rather broad and edged in its outer part with long ciliated setae. 



$HS.-MaT. CTp. 352. 30 



