178 
THE VOYAGE OF H.M.S. CHALLENGER. 
have examined, which have, however, a similar spot on the preceding (penultimate) 
joint of the same legs, but as these colour-markings apparently vary in other species 
(as e.g., Neptunus {Amphitrite) hcistatoides ) they can scarcely be regarded as evidencing 
the distinctness of Neptunus gladiator and argentatus. 
Neptunus ( Amphitrite ) spinipes, n. sp. (PI. XV. fig. l). 
The carapace is rather narrow and convex for a species of this genus, its surface is 
everywhere rather obscurely granulated, and is covered with inequalities or rounded pro- 
minences, which are most distinctly developed on the cardiac and branchial regions. The 
front is armed with six teeth, the median and submedian projecting much more than the 
lateral teeth, and separated from one another by a concave interspace ; the median and 
lateral (or inner orbital) teeth are small and dentiform, the submedian teeth larger and 
triangulate. The antero-lateral marginal teeth are small (the two following the exterior 
orbital tooth the smallest), and are dentiform rather than spiniform ; the lateral epi- 
branchial spine (in the largest example), scarcely exceeds one-fifth the greatest width 
of the carapace ; the postero-lateral margins are concave, and form nearly a right angle 
at their junction with the straight posterior margin, but the postero-lateral angles are 
not spinuliferous, as in Neptunus hastatoides ; the orbits are deep, in a dorsal view 
almost semicircularly concave ; the sternal surface of the body is polished and very 
distinctly granulated ; the post-abdomen (in the male) is very narrow in its distal half, 
and composed of only five distinct joints, the second and third, and the fourth and fifth 
segments having coalesced. The eyes are large and short ; the basal antennal joint 
barely reaches the subfrontal process, and does not reach to the apex of the inner sub- 
ocular lobe of the orbit ; the outer maxillipedes are rather thinly clothed with longish 
hairs, which also extend over the subhepatic and pterygostomian regions of the body; 
the merus of the outer maxillipedes is narrowed towards its distal extremity, which is 
rounded. The chelipedes are subequal, very obscurely granulated, and covered with a 
close whitish pubescence ; the merus is armed with three spines on its anterior margin, 
and two on its posterior margin (whereof one is at the distal extremity), the carpus with a 
spine on its inner margin, and one on its outer surface, the palm with two spines on its 
supero-internal margin (whereof the distal one is small and placed just above the base of the 
dactyl), and one at the base near the articulation with the wrist ; both dactyl and pollex 
are straight, closely denticulated on their inner margins, and incurved at the tips. The 
second to the fourth legs are slender, compressed, and have the inferior margins of the 
penultimate joints and dactyli fringed with close-set hairs ; the fifth (swimming) legs are 
moderately robust, the merus-jointS are armed with a spine at the distal end of its 
posterior margin, and the terminal joints rather narrow-ovate and ciliated on the margins. 
