CRUSTACEA CASPIA. 285 



Bay Bogutui Kiiltiik, and the Srd (St. (io) lying Sun.^,.: * farther south 

 than the hitter. 



In the collection of Dr. Grimm this species is likewise represented only 

 hy (luite solitai-y specimens collected in the southern and middle i)art of the 

 Caspian Sea, the depth varying fri)m 7 to 20 fathoms. 



21. Niphargoides aequimanus, (». 0. Sars, n. sp. 



(PI. XVIII, lios. 14-23). 



Specific Characters. — Very much like the last described species, as to 

 outca' appearance, but of much smaller size. Cephalon considerably exceeding 

 in length the 1st segment of mesosorae, and having the lateral lobes rather 

 produced and rounded at the tip. Anterior pairs of coxal ])lates comparatively 

 smaller than in N. quadrimanus, and fringed with scattered bristles distally; 

 1st pair somewhat expanded in their outer part; 4th pair fully as broad as 

 they are deep. Epimeral plates of metasome well developed and quite smooth. 

 Urosome without any spines dorsally. Eyes comparatively small. Antenna' 

 of a structure similar to that in N. quadrimanus, but with a less number 

 of articulations in the flagella. Gnathopoda almost exactly alike both in 

 structure and size, propodos in both pairs oblong quadrangular, with the 

 palm much shorter than the hind margin. Pereiopoda resembling those in 

 N. quadrimanus, except that the basal joint of last pair is still more ex- 

 panded. Last pair of uro])oda comparatively more elongated than in the said 

 species. Telson with the lateral lobes scarcely diverging, each armed at the 

 tip with 2 unequal spines. Length of adult male .5 mm. 



Remarks. — This form is very nearly allied to N. quadrimanus, and 

 may easily be confounded with it. On a closer examination, it is, however, 

 found to differ, not only by its small size, but also in some structural de- 

 tails, especially in the structure of the gnathopoda and the shape of the 

 basal joint of the last pair of pereiopoda. Finally the last pair of uropoda 

 are more elongated, and the lateral lobes of the telson scarcely diverging. 



Description of the male. — The length of an apparently adult specimen 

 measures only 5 mm., and this form is accordingly much inferior in size to 

 the other known species. The form of the body (see fig. 14) is rather slender 

 and somewhat compressed, bearing on the whole a strong resemblance to 

 that in N. quadrimanus. 



The cephalon is almost as long as the first 2 segments of the mesosorae 

 combined, and has the lateral lobes rather prominent and narrowly rounded 

 at the tip. 



^u3.-MaT. cip. 193. II 20 



