1882. ] CRUSTACEANS FROM MAURITIUS. 541 
smaller spines ; the wrist has its upper margin subcarinated, with a 
spine at the distal end, behind which are several granules; the palm 
is nearly three times as long as broad, laterally somewhat compressed, 
with the upper and lower margins subacute—the upper armed with 
ten small tubercles and with a short spine placed above the base of 
the dactylus, which is much thickened at base and has its inner mar- 
gin unarmed ; except for asmall tubercle at base, it curves downward 
nearly at right angles with the base against the small immobile finger, 
which is armed with two blunt teeth on its inner margin. The ambu- 
latory legs are slender and smooth; the merus joints are armed 
below with a small distal spine, and are longitudinally canaliculated 
on their outer surface ; traces of similar canaliculi are seen upon some 
of the following joints, and particularly of the dactyli, which are hairy. 
The distal portions of the terminal segment and uropoda are mem- 
branaceous and minutely ‘spinulose as in the typical Palinuri, the 
margins of the indurated parts being denticulated nearly as in P. 
vulgaris. 
The ground-colour of the carapace (in the dried example) is red, 
blotched or variegated with yellow; the postabdominal segments 
are orange-red, minutely punctulated with yellow ; and the first to fifth 
segmerits have a transverse series of large yellowish-white spots 
bordering their posterior margins and the margins of the lateral 
lobes and spines ; the flagella of the antenne are alternately banded 
with yellow and red; the ambulatory legs are orange-yellow, with 
numerous irregular yellowish-white spots. The length of the body 
is a little over 6 inches (152 mm.), of the left chelipede about 64 
inches (160 mm.), of the first ambulatory legs nearly 47 inches (108 
mm.). The unique example being dried, and the parts not always 
fully extended, it is difficult to give the exact measurements. 
A single adult male isin the collection (preserved dry). 
The Mauritian variety is to be distinguished from the West-Indian 
type of P. longimanus (if Prof. A. Milne-Edwards’s outline drawings 
may be referred to for these minute details) only by the minute or 
obsolete second lateral postocular spine, the stouter leg of the first pair 
with more robust palm and stronger abruptly-curved dactylus, by 
the much greater development of the spines of the peduncular joints 
of the antennze, and the existence of a spinule behind the long lateral 
spines of the second to fifth postabdominal segments—distinctions 
which, even if they exist, assuredly cannot be regarded as of specific 
importance. 
Although P. longimanus differs so markedly from its congeners 
in the form and great development of the chelipedes, in what are 
usually regarded as the essential generic characters—i. e. in the dis- 
tinct rostrum, the narrow antennal segment, approximated bases of 
the antennz, and short anteunulary flagella—it belongs, as already 
stated, to the typical Palinuri. 
The genital apertures are situated upon a slender styliform pro- 
longation of the coxal joints of the fifth ambulatory legs, which is 
directed inward toward the middle line of the sternum, and bears a 
small spine near the distal extremity. In P. vulgaris the rounded 
