1882.] CRUSTACEANS FROM MAURITIUS. 



541 



smaller spines ; the wrist hcis 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 a small 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 anrbu- 

 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 canalicidi 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 Palimiri, i\\Q 

 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 

 segments 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 antennas 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 liitle over 6 inches (1.52 mm.), of the left chelipede about 64 

 inches (160 mm.), of the first ambulatory legs nearly 4^ 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 is in 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 antennae, and the existence of a spinule behind the long lateral 

 spines of the second to fifth postabdominal segments— distuictions 

 which, even if they exist, assuredly cannot be regarded as of specific 

 importance. 



Although P. lovgima7ius differs so markedly from its congeners 

 in the form and great development of the clielipedes, in what are 

 usually regarded as the essential generic characters— 2. e. in the dis- 

 tinct rostrum, the narrow antennal segment, approximated bases of 

 the antennae, and short antennulary 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 Hue of the sternum, and bears a 

 small spine near the distal extremity. In P. vulyaris the rounded 



