CRUSTACEA CASPIA. 427 



The last pair of epimeral plates of the metasome have the lateral corners 

 pointed, but comparatively loss produced than in P. caspitis. The urosome 

 has across its 1st segment, somewhat in front of the middle, a very distinct 

 saddle-like depression. 



The eyes are somewhat less regularly oval than in the preceding species, 

 having their upper part narrowed to an obtuse point. 



The superior antennae are about the length of the cephalon and the 4 

 anterior segments of the mesosome combined, and have the 1st joint of the 

 peduncle (see fig. 22) exceedingly large, and conspicuously applanated. The 

 flagellum is rather slender and composed of a much greater number of 

 articulations than in the preceding species, amounting to from 30 to 40. 

 The accessory appendage is likewise more fully developed, consisting of 6 

 articulations. 



The inferior antennae are but little longer than the superior, and have 

 the flagellum divided into 34 articulations. 



The anterior gnathopoda are constructed as in the preceding species, 

 but have the propodos (see fig. 23) somewhat shorter in proportion to its 

 breadth and less obliquely truncated at the tip. 



The posterior gnathopoda could not be examined more closely, as they 

 were hidden between the coxal plates. 



The pereiopoda seem on the whole to agree very closely with those in 

 P. caspius, but are more densely setiferous and have the posterior edge of 

 the basal joint in the 3 posterior pairs divided into a greater number of 

 serrations. 



As to the uropoda and telson, they do not seem to differ in any essential 

 manner from those parts in P. caspius. 



Occurrence. — Of this form 2 specimens are contained in the collection 

 of Dr. Grimm, the one preserved in spirit, the other in glycerine, both being 

 in a very good state of preservation, which prevented me from sacrificing 

 either of them for a closer anatomical examination. The specimens, which 

 exactly agree both as to size and other characters, were collected by 

 Dr. Grimm at Stat. 124, belonging to the middle part of the Caspian Sea, 

 from a depth of 40 fathoms. 



Fam. PONTOPOREIID^. 



Gen. Pontoporeia, Kroyer. 



Remarks. — Of this genus only 2 species have hitherto been recorded, 

 the one, P. femorata, Kroyer, being an exclusively marine form, whereas 

 the other, P. affinis Lindstrom, also occurs in the great lakes of Norway, 



4ii8.-MaT. CTp. 257. 7 



