(ἄχχγη] CRUSTACEA ΟΑ8ΡΙΑ. 59 
antennal scales, the uniform structure of the pereiopoda, and by the very 
shallow apical sinus of the telson, and its peculiar comb-like armature. Mr. 
Czerniavsky refers to this genus 5 species, one of which, M.: Kröyeri, 
should, however, perhaps more properly be placed within the genus Austro- 
mysis, whereas another form described by that author as a Paramysis; must 
find its place in the present genus. As far as yet known, the genus is not 
represented beyond the Caspian and Black Seas, one of the species, M. la- 
custris, having, however, been found in a lake among the mountains of 
Caucasus. In the Caspian Bea (he genus is represented by 5 species, one of 
which is now for the first time established. 
: 2. . Mesamysi Ullskyi san 
| fi οι. mm 
ee UNskyi 1) Czerniavsky, Le fasc. 2. p. 65, Pl. XXVI, figs 13—23. 
Specific. Characters, — Body (see PI. III, fig. 1) very slender and elon- 
gated, with the anterior division rather attenuated in front, and scarcely longer 
than the 4 anterior segments of metasome combined. Carapace deeply emargi- 
nated posteriorly, leaving the dorsal part of the last 2 segments of mesosome 
uncovered, cephalic part scarcely as broad as the Ist segment of metasome, and 
having theanterior edge nearly straight; frontal spine large, uncovered, Me- 
tasome very elongated, ‘and. gradually tapering posteriorly. Eyes of moderate 
size , projecting s somewhat beyond the sides of the carapace, corneal part rather 
expanded and distinetly emarginated on the dorsal face. Peduncles of the 
Superior antenne (fig. 2) conspicuously elub- shaped, the last joint being con- 
siderably. dilated. and having at the inner corner about 10 strong plumose 
sete. Antennal scales (see fig. d of middle size, “exceeding the peduncles ‘of 
the superior antennæ by about !/, of their Agen form oblong linear, the 
breadth equalling V4, of the tenth” ‘terminal part projecting beyond the 
outer corner occupying about .'/, of the length | of the scale, apical segment 
well defined, bearing 5 of the marginal setæ (see fig. 4). Pereiopoda (fig. 11) 
moderately, slender, with the meral joint a little shorter than the ischial 
one, tarsal part somewhat longer than the former, with the ‘Ist joint much 
shorter. than the other 3, which are nearly equal-sized, düctylar' joint (see 
fig. 12) very ‘small, with the terminal claw nearly setiform. Telson (fig. 1) 
comparatively large, “exceeding ‘somewhat in length the last segment of me- 
tasome, and gradually tapering distally, lateral edges nearly straight, ‘and 
armed each with, from 18 to 22 spinules, E outermost E Leges is ‘some: 
5 SES 1) 4.2 may be ‘noted, ibd this species in othr parts οἱ the work ο Para- 
‘mysis Sträliihi, and that the type specimens are labelled in 
Melanges biologiques. T. XIII, p. 407. 
