175 



scarcely broader than the 2 succeeding pairs; 4th pair much more deep than 

 broad, lower edge shorter than the hind margin. Metasome and the posterior 

 part of mesosome distinctly keeled dorsally. Last pair of epimeral plates of 

 metasome produced at the lateral corners to a spiniform projection, posterior 

 edge evenly convex in the middle. First segment of urosome with a very 

 slight dorsal carina. Corneal lenses distinct, the lower pair placed within a 

 small sinus of the inferior edges of the cephalon, at a short distance from 

 the lower corners of the front; underlying pigment well-defined and bright 

 red. Superior antennae in female about 3 times the length of the cephalon, 

 and considerably projecting beyond the peduncle of the inferior ones, flagellum 

 2 and a half times as long as the peduncle, and composed of about 30 arti- 

 culations clothed posteriorly with fascicles of slender seta?. Inferior antennae 

 twice the length of the superior, with the 2 outer joints of the peduncle 

 nearly equal-sized. Both pairs of gnathopoda rather slender, but especially 

 the posterior ones; propodos in the former a little shorter than the carpus, 

 and oblong oval in form; in the latter about half as long as the carpus, and 

 sublinear. Dactylus of the anterior pairs of pereiopoda very slender and 

 considerably exceeding in length the 2 preceding joints combined. The 2 

 succeeding pairs, with the propodal joint produced beyond the short recurved 

 dactylus, to a compressed setiferous lobe. Last pair of pereiopoda with the 

 basal joint considerably exceeding in length the remaining part of the leg, 

 posterior expansion somewhat irregular in form, obliquely truncated, and 

 strongly rounded at the inferior corner, which reaches almost to the end of 

 the meral joint ; carpal joint rather broad, nearly heart-shaped, and considerably 

 projecting anteriorly, propodal joint very narrow, and shorter than the 2 

 preceding joints combined, dactylus narrowly lanceolate, and exceeding half its 

 length. Last pair of uropoda with the rami lanceolate, twice as long as the 

 basal part, and fringed with ciliated bristles, besides a few spinules. Telson 

 oblong and quite naked, excepting for a small apical denticle on each side. Body 

 semipellucid, with a faint yellowish tinge, and mottled with orange and 

 pinkish pigment. Length of adult female reaching 25 mm. 



Eemarlts. This is the first described species of the genus, and is 

 readily recognized from most other species, not only by its large size, but 

 also by several other well-marked characteristics, thus by the distinctly keeled 

 posterior part of the body, by the form of the cephalon and the last pair ol 

 epimeral plates of metasome; furthermore, by the mutual length of the antenna 1 , 

 and by the structure of the last pair of pereiopoda, The Awju'ti^-ii IHII<-HK 

 of Stimpson, as described by Sp. Bate, would seem to be this species, at least 

 to judge from its large size. The two imperfect]}- described species, named 

 by Boeck as A. dubia and propinqva, must be cancelled, as I have found, on 



