Boone, Cmstacea, Cruise of "Alva," 1931 123 



the cornea. This tooth is more obscure in A. gracilis than is that 

 of A. naifaroensis Coutiere, but is also distinctly defined, therefore 

 not to be confused with A. nitescens. In the present species, the 

 tooth is separated from the rostrum by a small, acute incision, the 

 "tooth" being closely appressed to the rostrum and the incision 

 nearly linear. The small supraorbital tooth is absent, there being 

 only a slight pinching in, or crease, in the carapace defining the 

 base of the rostrum from the orbital border, which presents an 

 uninterrupted concave margin, not even possessing that "more or 

 less obtuse prominence" that de Man accredits to nitescens. 



The cornea is large, ovoidal, closely encupped by the carapace 

 margin, the distal corneal margin extending about one-half of the 

 length of the dorsally visible portion of the first peduncular article 

 of the antennulae. 



The antennulae are thick and have the first article extending 

 two-thirds of the length of the rostrum ; the second article extend- 

 ing as far as the apex ; the third article is about one and one-half 

 times the length of the second article, and reaching as far for- 

 ward as does the scaphocerite ; the flagellum is fleshy, composed 

 of ten articles and a terminal stylus ; the inferior margin bears 

 a coarse brush of setae ; the inferior whip is slenderer, about twice 

 as long as the other one ; the stylocerite is a long, narrowed, acumi- 

 nate triangle, the apex of which extends to midway the third 

 article of the antennular peduncle. 



The antennae have a strong basal article, which has the outer 

 distal margin in profile with two pointed lobes, one above, and 

 the longer apex below the scaphocerite ; the second and third ar- 

 ticles are cylindrical, thickened, considered together, are as long as 

 the scaphocerite and also equal in length to the antennular pe- 

 duncle ; the flagellum is fine, about as long as the body. The scapho- 

 cerite is short, about three-fourths as wide as long, with the outer 

 distal angle a sharp tooth, the distal and inner lateral margins 

 convex, ciliate. 



The abdominal terga are moderately rounded dorsally, with 

 the lateral margins overlapping, not much produced, forming an 

 almost unbroken line along their lateral margin, which is only pro- 

 jected about two-fifths of the length of the pleopodal peduncle be- 

 yond the ventral wall. The first abdominal segment is the short- 

 est ; the second segment is one and one-third times as long as the 

 third segment ; the third to sixth segments, inclusive, are approxi- 



