T. XIIl] CRUSTACEA CASPIA. 405 



Remarks. — This form has been rather minutely described by Mr. 

 Czerniavsky, but the peculiar development of the exognath of the 2 pairs 

 of maxillae would seem wholly to have escaped his attention. It is a very 

 magnificent species, and easily recognizable from most of its allies, both by 

 its comparatively large size and by the shape of the antennal scales and of 

 the telson. Besides the typical form, Mr. Czerniavsky speaks of a variety 

 „lateralis", observed in a single immature specimen, which, according to 

 that author, distinguished itself by a somewhat larger cornea, and by the 

 telson being less prolonged and attenuated, and having moreover the apical 

 incision extremely shallow. 



Occurrence. — The species has been observed in several places of the 

 Caspian Sea. Mr. Czerniavsky quotes the following localities: Northern part 

 of the Caspian Sea (Ullsky), Mangischlak (Uli sky), southern part of the 

 Caspian Sea (Ullsky), the harbour of Astara (Goebel), the promontory 

 of Zelenyi Bugor (Goebel), and for the variety, littoralis, Petrowsk or 

 Baku (Goebel). — The species was also represented in the collection of 

 Warpachowsky by a few beautifully preserved specimens, which occurred 

 at Stat. 15 off the Tschistyi-Bank, lying at some distance south of the 

 estuary of the Wolga. 



2. Paramysis armata, Czerniavsky. 



Paramysis armata, Czerniavsky, 1. c. fasc. 2, p. 63, PI. XXIX, figs 16 — 25. 



Remarks. — I have only seen a fragment of this form, comprising the 

 anterior part of the carapace with the eyes and antennas, which was con- 

 tained in the type collection of Caspian Mysidse arranged by Mr. Czer- 

 niavsky. To judge from this fragment, the present species is very nearly 

 allied to P. Baeri, scarcely differing except in the eyes being comparatively 

 smaller, and having the corneal part far less expanded. 



Occurrence. — According to Mr. Czerniavsky, a single female spe- 

 cimen of this form was collected by Lieutenant Ullsky of Mangischlak. 



Gen. 2. Mesomys, Czerniavsky, 1882. 



Generic Characters. — Form of body (see PI. Ill, IV, V & VI, fig. 1) more 

 or less slender. Carapace deeply emarginated posteriorly, and but imper- 

 fectly covering the posterior part of the mesosome, anterior edge not angu- 

 larly produced in the middle; frontal spine uncovered. Eyes (see PI. IV, V, 

 VI, fig. 2) large, pyriform. Superior antennas (PI. Ill, fig. 2) of the usual 

 structure. Inferior antennas (PI. Ill, IV, V, VI, fig. 3) less strongly produced 

 at the outer corner of the basal part than in Paramysis, scale of moderate 



Enlletin N. S. IY (XXXVI) p. 57. 



