208 G. 0. SARS. 



l)Osterior edge boldly curved below tlie middle; that of last pair having the 

 posterior expausiou produced below to an obtusely truncated lobe reachiug 

 almost to the middle of the raeral joint. Uropoda nearly as in the preceding 

 species. Telson without any spines, and having the terminal lobes obtusely 

 pointed, each being tipped by 3 fine hairs. Length of adult female 6 mm., 

 of male 8 mm. 



liemarks. — This new sjjecies is very nearly allied to the i)receding 

 one, but unquestionably specifically distinct. Besides by its much inferior 

 size, it differs in the anterior part of the back being quite smooth, without 

 any trace of a keel, in the last dorsal projection not differing in shape from 

 the preceding ones, and in the rather different form of the basal joint of the 

 last 2 pairs of pereiopoda, finally, in the telson having no trace of any spines. 



Description. — The length of adult, ovigerous female specimens is about 

 6 mm., and that of male specimens scarcely exceeds 8 mm. This form is 

 consequently much inferior in sexe to the preceding species. 



The general form of the body nearly agrees with that in A. cristata, 

 and there is a quite similar difference between the 2 sexes as described in 

 that species, the females l)eiug somewhat shorter and stouter than the males. 

 On this cause I have regarded it sufficient for the recognition of the species 

 to figure only one of the sexes, in this case the male (fig. 9). In both sexes 

 the anterior part of the back is quite evenly rounded, without any trace of 

 a keel. In the 5th segment of the mesosome there is found in some specimens 

 a very slight approach to a keel, but in no specimen this keel is elevated in 

 the form of a dorsal projection. In the 5 succeeding segments, on the other 

 hand, the dorsal i)rojections are very distinctly developed, being rather pro- 

 jecting and of an acutely triangular shape. The last of these projections 

 does not differ much from the others, being, as the latter, acutely produced, 

 not, as in the preceding species, rounded. The segments of the urosome are, 

 as in that species, without any dorsal keel or projections, but provided with 

 a similar supply of fine hairs and small subdorsal spiuules. 



The cephalon (fig. 10) does not differ much in its form from that in A. 

 cristata. 



The coxal plates are comparatively somewhat less deep than in the pre- 

 ceding species and also narrower, otherwise of a much similar appearance. 



This also applies to the epimeral plates of the metasome. 



The eyes (see fig. 1 0) are comparatively larger than in A. cristata, and 

 of a pronounced reniform shape, their anterior edge being distinctly insinu- 

 ated in the middle. 



The superior antennae (see fig. 9) are very slender, and considerably ex- 

 ceed in length half the body. The 1st joint of the peduncle does not much 



"fus.-Max. cxp. 20S. 3Q 



