466 PROFESSOR CHARLES CHILTON ON THE 
First gnathopod (fig. 6) moderately stout ; basal joint stout, of equal width through- 
out; a few tufts of long setze near the distal end of its posterior margin ; ischium, merus, 
and carpus all short, subequal, and all bearing long setz on the posterior margin ; 
carpus also with tuft at the antero-distal angle; propod at base as wide as the distal 
end of the carpus, narrowing slightly distally; anterior margin straight or slightly 
curved, and with tufts of long sete; posterior margin slightly concave distally, and 
bearing numerous long sete in tufts; the palm transverse, straight, defined by two 
long spinules ; finger long, extending beyond the palm. 
Second gnathopod (fig. 7) slender; basal joint curved ; ischium much longer than 
the merus; carpus longer than the propod, which is narrowed at base, slightly curved ; 
palm rather short and slightly oblique; the posterior margin of the merus is furred 
and bears three tufts of long sete towards the distal end; carpus furred on both 
margins, with tufts of long sete on the lateral surface and anterior margin at distal 
end, and several tufts, or short transverse rows, on the distal half of the posterior 
margin; propod with both margins furred, and tufts of long sete on their distal 
portions, those on the anterior border towards the base of the finger forming a dense 
group of very long sete. The first and second perzeopoda rather slender; the merus 
shghtly broadened and produced at the antero-distal angle; propod somewhat curved ; 
finger about half as long as the propod, slender, curved, smooth. ‘The third, fourth, 
and fifth perseopoda are of increasing lengths, all having the merus much broadened 
and produced, the propod curved, and the finger long, as in the first and second 
pereeopoda ; basal joint of all expanded, that of the third rounded posteriorly, those of 
the fourth and fifth somewhat angled below, and with the posterior margin convex 
in its upper part and straight or slightly concave below, the hind margins feebly 
crenulate. 
First uropods with the branches slender, subequal, longer than the peduncle, 
marginal spines on the peduncle and on the outer branch. Third uropod with peduncle 
large, shorter than the branches, which are subequal in length, lanceolate, margins 
fringed with short spinules and long plumose hairs, the inner branch with small second 
jot. Telson reaching nearly to the end of the third uropod, apparently without 
spines on its dorsal surface. 
This species differs from the typical species A. gigantea Chevreux in having both 
gnathopoda subchelate and the first not slender but moderately stout. As there are 
only the two species known, it will be well to slightly widen the characters of the genus 
to include the species now being described. ‘The typical species was of enormous size, 
one of the specimens being as much as 140 mm. long; probably when specimens of 
both species of an intermediate size are known, it will be found that the two are more 
nearly alike than appears from the detailed description above, which is based on the 
single specimen obtained by the Scotva. 
