82 ME. E. J. MIEES ON THE IDOTEID.E. 



the four anterior segments of the thorax have the posterior margin 

 narrower than the anterior, with the antero -lateral angles some- 

 what prolonged forward ; the last three segments, on the contrary, 

 have the anterior margin narrower than the posterior, and the 

 postero-lateral angles enlarged and prolonged backward. Postab- 

 domen rather more than one fourth the length of the animal, with' 

 three very distinct segments ; the second segment with two 

 rather obscure transverse sulci. Eyes red, occupying the antero- 

 lateral angles of the head. Anteunules approximated at base, 

 and more slender than the antennae, which are brownish or yellow, 

 and reach only to the third thoracic segment. Legs yellowish. 

 Colour brownish, mingled with pale yellow, and with a longi- 

 tudinal median line, which occupies the whole length of the 

 thorax. Length about 4 lines (in the plate -^^ inch, about 

 10 millim.). 



In the figure the sides of the body are nearly parallel, and there 

 are six distinct postabdominal segments, the first five being very 

 short, and the last semicircularly rounded at its distal end. The 

 antennae are 5-jointed, without a distinct flagellum, the last 

 joint similar to the preceding, on which account I place the 

 species, provisionally at least, in Cleantis. As the name Idotea 

 angustata has been preoccupied by Lucas, I would propose to 

 designate this species, if distinct, Cleantis Gayi. It may be iden- 

 tical with Cleantis linearis, Dana, in which, however, the angles 

 of the thoracic segments are less prominent, and the terminal 

 segment truncated or even slightly excavated at its distal extre- 

 mity. If, on the other hand, a distinct flagellum exist, the species 

 must be placed in Idotea — Idotea prismatica. 



Cleantis gea-Nitlosa. 



Cleantis granulosa. Heller, Verhandl. zool.-bot. Fereins, Wien, xi. 

 p. 497(1861); id. Cr.in Reise der Novara, p. 132, pi. xii. fig. 2 (1865). 



Body very narrow, broadest at the two anterior segments, 

 narrowing very slightly from before backward, with the post- 

 abdomen as broad as the posterior margin of the thorax. Frontal 

 margin of the head slightly emarginate in the middle ; its poste- 

 rior margin convex. Thoracic segments of equal length, broader 

 than long, strongly convex, with the sides perpendicular. The 

 antero-lateral angles of the first segment are only slightly pro- 

 longed forward. The postabdomen consists of five segments, of 

 which the two anterior are shaped like the preceding thoracic 



