REPORT ON THE SOHIZOPODA. 203 



since in most respects it would seem to agree pretty well with that genus. The telson, 

 it is true, has the apex not entire as in the typical species, Mysidopsis didelphijH; but 

 there is another species, undoubtedly belonging to this genus, viz., Mijsidopsis autjusta, 

 which likewise has the telson cleft at the tip, although the borders of the incision in that 

 species are smooth, and nf)t spinulose. 



Description. — Of the present form only a single mutilated specimen, an adult female, 

 was found in the collection. It has a length of about 8 mm. 



The form of the body (sec PI. XXXV. fig. 21) is comparatively slender, about as in 

 the northern form Mi/sidopsis angiista, but with the anterior division somewhat more 

 dilated. 



The carapace, as in the other species of this genus, is rather small, not nearly covering 

 the whole of the trunk, the two posterior segments of wliich appear almost wholh- 

 exposed behind. Its anterior third is marked off by a well-defined cervical impression, 

 and is slightly arched above. The frontal margin forms only a very slight angular 

 projection in the middle, and the antero-lateral corners are olitusely rounded. 



The caudal segments are all regular cylindrical, and the last of them somewhat longer 

 than the rest. 



The eyes are comparatively large and slightly flattened, with the cornea much 

 expanded and deeply emarginate above. The ocular pigment is of the usual dark 

 hue. 



The antennular peduncle does not attain any considerable length, and exhil)its the 

 usual structure. Both of the flagella were broken near their bases. 



The antennal scale (fig. 22) projects only beyond the antennular peduncle by about 

 one-fourth of its length, and exhibits a narrow lanceolate form, with l)nih margins 

 setiferous throughout their whole length. The apical articulation is rather smdl, and 

 bears four of the marginal sette. The proximal part of the flagellum is much shorter 

 than the scale, and has the middle joint largest. The terminal part was broken in the 

 specimen examined. 



Of the legs only one of the second pair remains in the specimen. Its structure would 

 seem to agree perfectly well with tliat in the other species, except that the joints ;ue 

 somewhat less expanded. 



The two posterior pairs of incubatory lamellae composing the marsupial pouch are 

 seen in the fig. 21 ; the anterior rudimentary pair would seem to have been thrown ofl' 

 along with the corresponding legs. 



The caudal limbs do not exhibit any peculiarities in their structure. 



The telson (see fig. 23) is somewhat shorter than the last caudal segment, and 

 exhibits the usual triangular form, being broadest at the base and tapering rapidly toward 

 the apex, with the lateral edges almost straight, and armed on either side with close upon 

 sixteen small denticles, disposed throughout their whole lengtli. The apex is not, as in 



