426 0- 0. SARS, 



The last pair of uropoda (fig. 19) project but slightly beyond the others, 

 and have the basal part comparatively short, otherwise agreeing with the 

 preceding pairs in the simple mucronate shape of the rami. 



The telson (fig. 20) is entire, squamiform, about as long as it is broad 

 at the base, and has the tip slightly produced in the middle with a small 

 notch on each side, from wliich a minute hair issues. In the arctic species 

 the tip exhibits traces of a slight emargination. 



Occurrence. — This form has been collected by Dr. Grimm in 4 Stations 

 belonging to the middle part of the Caspian Sea, the depth ranging from 

 80 to 250 fathoms. 



2. Pseudalibrotus platyceras (Grimm). 



(PI. 1, figs. 21—23). 



Onesimus platyceras, Grimm MS. 



Specific Characters. — Very like the preceding species, but about twice 

 as large and comparatively more tumid, with the back broadly rounded. 

 Lateral lobes of cephalon subangular. Anterior pairs of coxal plates com- 

 paratively broader than in P. caspius. Last pair of epimeral plates of meta- 

 some less acutely produced. Urosome with a conspicuous saddle-like de- 

 pression across the anterior part of the 1st segment. Eyes narrowed in 

 their upper part. Superior antennae with the 1st joint of the peduncle 

 very large and applanated, flagellum composed of a greater number of arti- 

 culations than in tlie preceding species, accessory appendage exceeding half 

 the length of the peduncle, and 6-articulate. Gnathopoda, pereiopoda, uro- 

 poda and telson apparently of a similar structure to that in P. caspius. 

 Length nearly 20 mm. 



Remarks. — This form is very nearly allied to the preceding one, but 

 apparently distinct, being fully twice as large. For want of specimens, how- 

 ever, a closer anatomical comparison of the two could not be instituted. 



Description. — • The length of an adult female specimen attains to nearly 

 20 mm., and this form accordingly grows to a much larger size than the 

 preceding one, and in this respect even exceeds the arctic species. 



The form of the body (see fig. 21) on the whole closely resembles that 

 of the preceding species, though still more robust and rather tumid, with 

 the back broadly rounded. 



The cephalon but slightly exceeds in lengtli the 1st segment of the 

 mesosome, and has the lateral lobes subangular in front. 



The coxal plates appear somewhat broader than in the preceding species, 

 though exhibiting an exactly similar mutual relation. 



4'U3.-Mai. cxp. 256. 6 



