PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 431 
than the telson, and, except a small portion near the base, are thin and 
transparent like the terminal part of the telson. 
Measurements. 
Meneih tron frontiof carapax:to-tip of telson ..22...-.--.-2.2<-.ccecl cece ccccce ce 
bene ih irom tips. of antenne to-tip of telson.---.--.--cs-2-<.ccs<<222ceencece 23.2 
Heneth of carapax along median line above ..-....--....--.2.2202.0--se0 scence 6.2 
Penxeh Oncairapax along lateral margin.............--221 .22-2- -- 2 nee weecer ace 9.0 
Br onceCMimuLe re bie OMmCALAPASG sao wet e ls ak aes Voce fe an cose sce eee ee 8.3 
So MAEPDeELWeCH aTLGMOr Angles: -. 5. 0.01.2. 12 bs eo eee hae eco ees ceneee tas 
PMN PEMMECNGINOUAY Ros isPe oS 2/5 (N02) Port cee eeu sl ees then Mle 6. 2 
(re uiosiaubreknessior cephalo-thorax<-¢-.255.s\sacmsae see ooioseGccinew cass oso see a 
Breadth of first somite of abdomen~...-...........---.------ SR cop i cee igs ba 6.1 
PMeainOmsext hn SOMte OL ADMOMEN « ..—.-<e occ cos ek. 2= acnce cases cee ones seein 4.0 
Station 872; 86 fathoms. 
In the outline of the edges of the segments of the antennie and in the 
divisions of the carinz of the carapax this species is much like A. Ameri- 
canus Smith (Amer. Journ. Sei., IL, xlvii, p. 119, 1869; Scyllarus (Arctus) 
Gundlachi von Martins, Archiv fiir Naturgesch., xxxvili, p. 123, pl. 5, 
fig. 13, 1872), the young of which it may possibly prove to be, though 
this seems very improbable considering that the specimen just described 
is half as long as ordinary specimens of A. Americanus, which is known 
from the Gulf of Mexico and the West Indies. 
Nephropsis aculeatus, sp. nov. 
Very closely allied to Nephropsis Stewarti Wood-Mason (Journ. Asiatic 
Society of Bengal, xlii, part ii, p. 39, pl. 4, 1873), described from a single 
female, 98"" long and wanting the chelipeds, dredged in 260 to 300 
fathoms in the Bay of Bengal. 
Male.—In specimens 30" to 34™ in length the rostram is very slightly 
longer proportionately than represented in the figures of . Stewarti, 
but in all other respects the carapax shows no differences whatever. The 
abdomen is as represented in the figure of N. Stewarti, except that the 
pleura of the second to the fifth somite, inclusive, project farther down- 
ward and terminate in slender, acuminate, and spiniform tips, and that 
the pleuron of the sixth somite is sharply right-angled below, and not 
rounded. The uropods and telson show no differences whatever. 
The chelipeds are equal, or very nearly so, about a fourth longer than 
the carapax, including the rostrum, and are carried with the chele held 
horizontally, as in Nephrops and Homarus. The merus is about as long as 
the rostrum, and is armed near its distal end with a slender spine above 
and a similar one below. The carpus is short, a little longer than broad, 
slightly broader than the distal part of the merus, and is armed with 
three small spines—one near the middle of the inner edge, one at its 
distal end, and another beneath at the articulation with the chela. The 
chela is scarcely longer than the merus and slightly broader than the 
carpus, somewhat compressed vertically, rounded above and below, and 
