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 i)art of the telson. 



Measurements. 



mm. 



Length from front of carapax to tip of telson IH. 7 



Length from tips of autennic to tip of telson 23. 2 



Length of carapax along median line above 6. 2 



Lejigth of carapax along lateral margin 9. 



Greatest breadth of carapax 8. 3 



Breadth between anterior angles 7. 5 



Breadth posteriorly 6. 2 



Greatest thickness of cephalo-thorax 3. 5 



Breadth of tirst somite of abdomen (i. 1 



Breadth of sixth somite of abdomen 4.0 



Station 872 ; 80 fathoms. 



In the outline of the edges of the segments of the antennae and in the 

 divisions of the carinse of the carapax this species is much like A. Aynerl- 

 canus Smith (Amer. Journ. Sci., 11, xlvii, p. 119, 1869 ; Scyllarus {Arctus) 

 Gundlaehi von Martins, Archiv fiir Naturgesch., xxxviii, p. 123, pi. 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 N'ephropsis Sfeicarti Wood-Mason (Journ. Asiatic 

 Society of Bengal, xlii, part ii, p. 39, pi. 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 31""^ in length the rostrum is very slightly 

 longer proportionately than represented in the figures of M. Steicart% 

 but in all other respects the carapax shows no difierences whatever. The 

 abdomen is as represented in the figure of iV^. Steicarti, except that the 

 pleura of the second to the fifth somite, inclusive, project farther down- 

 ward and terminate in slender, acuminate, and spiuiform tips, and that 

 the pleuron of the sixth somite is sharply right-angled below, and not 

 rounded. The uropods and telson show no difierences whatever. 



The chelipeds are equal, or very nearly so, about a fourth longer than 

 the carapax, including the rostrum, and are carried with the chela? 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 i)art 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 



