On Ascension-Island Zoology. 433 
anterior legs (or chelipedes) in both specimens are very large 
and robust; arm or merus joint short, trigonous, with the 
margins unarmed; carpus or wrist large, with its inner margin 
produced into a broad squarely truncated lobe; both carpus 
and palm (as already noted) are punctulated above, the palm 
has its upper margin rounded, the lower margin straight, thin- 
edged, and entire ; there is a rounded prominence on the inner 
surface ; the fingers are black, dentated on their inner margins, 
with acute apices, the coloration not extending along the inner 
or outer surface of the palm. ‘The ambulatory legs are slender, 
smooth, and nearly naked, with the penultimate and terminal 
joints longitudinally canaliculated, the longitudinal channels 
in the penultimate joints not always extending along the whole 
length of the jomts. Length of the specimen from Ascension 
Island about 1 inch (25 millim.), breadth about 14 inch 
(38 millim.). This specimen is a female (preserved in 
spirit); it is of a flesh-coloured tint, and bears numerous 
ova. It was received with the collection of fishes of H.M.S. 
‘Challenger.’ There is also a larger male specimen (preserved 
dry) in the British-Museum collection from St. Helena (/. C. 
Melliss, Esq.) : length nearly 1 inch 5 lines (354 millim.), 
breadth a little over 2 inches 3 lines (nearly 59 millim.). 
This specimen is of a more bluish pink hue. | 
The smooth but rather convex and very transverse cara- 
pace, which is marked neither with tubercles nor swlc7, and 
the absence of the three anterior teeth of the antero-lateral 
margins, suffice to distinguish this species from all with which 
I am at present acquainted. Nantho Bouviert, A. M.-Ed- 
wards*, from the Cape-Verd Islands (St. Vincent), if one may 
judge from the brief description, bears some slight resem- 
blance to this species ; but the carapace is much narrower, the 
front less deeply notched, and the antero-lateral margins have 
but a single obscure tooth near their posterior angles. 
It may be identical with the small bright orange-red-coloured 
crab, figured on a reduced scale, but not determined, by Mr. 
C. 8. Bate, in the work of the late Mr. J. C. Melliss on St. 
Helena (Crustacea,’ p-)206, pl. xxi. ae. 3) 1875). Mir. 
Melliss notes that it is very rare; but one specimen was 
brought to him from Break-neck Valley, on the leeward side 
of the island. The crab figured by Mr. Bate differs from the 
species now described in being much narrower in proportion 
to its length. I designate this species P. Melliss¢, after its 
original discoverery. 
* Rev. et Mag. Zool. xxi. p. 877 (1869). 
+ Whether the Museum specimen received from Mr. Melliss is that 
referred to by Mr. Bate is uncertain. It was received from Mr. Mellisg 
