T. XIIl] - CRUSTACEA CASPIA. 403 



basal lobe scarcely larger than the outer masticatory lobe, otherwise of 

 quite normal structure. Gnathopoda (PI. II, fig. 6) comparatively strongly 

 built, with the terminal joint lamellar, and armed along the exterior edge 

 with a row of strong denticulated spines, the outermost of which, represent- 

 ing the dactylus, is much the largest (see PI. II, fig. 7). Pereiopoda (PI. II, 

 fig. 8) of uniform structure and rather robust, with the ischial and meral 

 joints somewhat expanded, tarsal part divided into 4 articulations, dactylar 

 joint very small, with the terminal claw slender and well defined from the 

 joint. Outer sexual appendages of male (PL II, fig. 9) of moderate size, and 

 slightly bilobular at the tip. Third pair of pleopoda in male (PI. II, fig. 10) 

 biramous, with the outer ramus shorter than the inner and simple conical 

 in form, terminating in a slender spine. Fourth pair of pleopoda in male (PI. 

 II, fig. 11) having the outer ramus much elongated, forming a slender cylin- 

 drical stem divided into 6 articulations, and terminating in 2 somewhat un- 

 equal flagella, the inner of which is the shorter and Particulate, outer part 

 of both densely spinulose. Telson (PL I, figs. 11 & 12, PL II, figs 13 & 14) 

 much elongated and strongly attenuated distally, lateral edges spinulose, 

 tip slightly incised, the incision being bordered by only a few scattered 

 spiniform projections, terminal lobes each tipped by a strong spine. Uropoda 

 (see PL I, fig. 11) of normal structure, outer lamella much larger than the 

 inner. 



Remarks. — The present genus, established by Mr. Czerniavsky, is 

 very nearly allied to the genera Mesomysis and Austromysis of the same 

 author, though differing from both in a few particulars, for instance in the 

 comparatively more fully developed carapace, the rather different shape of 

 the antennal scales and of the telson, and finally, in the peculiar develop- 

 ment of the exognath of the 2 pairs of maxillae. Mr. Czerniavsky refers to 

 this genus 3 species, viz., P. Baeri, P. armata and P. Ullslcyi, but the last- 

 named form is unquestionably, as will be shown farther down, not a Para- 

 mysis, but a true Mesomysis. As far as yet known, the genus is not repre- 

 sented beyond the Caspian Sea. 



1. Paramysis Baeri, Czerniavsky. 



(Pi. I & II). 



Paramysis Baeri, Czerniavsky, Monographia Mysidarum imprimis Imperii Rossici, fasc. 2 

 p. 56, PL XXYII, PI. XXVIII, figs 1—16, PI. XXIX, figs 1—15. 



Specific Characters. — Body (see PL I, fig. 1, PL II, fig. 1) rather 

 strongly built, with the anterior division but little attenuated in front. Cara- 

 pace nearly obtecting the whole mesosome, leaving only the dorsal part of 

 last segment uncovered, lateral lobes even advancing somewhat beyond the 

 mesosome (see PL II, fig. 1); cephalic part fully as broad as the 1 st segment 



Bulletin N. S. IV (XXXVI) p. 55. 



