CRUSTACEA CASPIA. 431 



rudimentary than in the other 2 species. Telson comparatively large, cleft 

 very deep and fissure-like, lateral lobes obtusely truncated at the tip and 

 having several lateral bristles and a dense row of apical spines. Length of 

 adult male 7 mm. 



Remarks. — This new species is at once distinguished from the 2 pre- 

 viously described forms by the hody having no distinct lateral tubercles or 

 dorsal expansions. In the structure of the several appendages it nearly agrees 

 with them, though the last pair of uropoda and the telson exhibit well- 

 marked specific differences. 



Description. — The solitary specimen examined, which is an adult male, 

 measures in length about 7 mm., and this form is accordingly somewhat 

 inferior in size to the 2 species previously described by the present author. 



The body (see fig. 8) is moderately slender and, as in the other species, 

 much compressed, without, however, exhibiting any distinct lateral tubercles. 

 Nor are any of the segments elevated to dorsal expansions, though they 

 appear rather sharply marked off from each other. 



The cephalon does not attain the length of the first 2 segments of the 

 mesosome combined, and is somewhat narrowed in front, with the lateral 

 faces quite smooth. The rostral projection (see fig. 10) is well marked, and 

 the lateral lobes slightly produced and narrowly rounded in front. 



The anterior pairs of coxal plates are but little deeper than the cor- 

 responding segments, and of a shape similar to that in the 2 previously de- 

 scribed species; the 1st pair not being at all expanded distally, and the 4th 

 not much broader than the preceding ones. The 3 posterior pairs are rather 

 small. 



The epimeral plates of the metasome are normally developed, the last 

 pair being only slightly produced at the lateral corners. 



The urosome is of moderate size, and has dorsally at the end of the seg- 

 ments a few small hairs. 



The eyes (see fig. 10) are very small, and placed at some distance from 

 the lateral corners of the cephalon. They are oval in form and have a 

 dark pigment. 



The antennae exhibit the structure characteristic of the genus, being 

 rather slender and feeble, though not much elongated. The superior ones 

 somewhat exceed in length the inferior, and have the peduncle somewhat 

 longer than the flagellura, which is composed of about 10 articulations. The 

 accessory appendage (see fig. 9), as in the other species, is extremely small, 

 and uniarticulate. The inferior antennae have the last peduncular joint some- 

 what shorter than the penultimate, and the flagellum about half the length 

 of the peduncle. 



4>u3.~MaT. CTp. 261. 1 1 



