1882.] CRUSTACEANS FROM MAURITIUS. 539 



the figure i?howt(l ilislinct differences in the proportions of the 

 penultimate joints and dactyli of the chelipedes, and in the coloration 

 of the ambulatory legs, and as Milne-Edwards in his later diagnosis 

 mentioned the existence of seven scries of spines on the carapace, a 

 character scarcely applicable to the specimen from the Mauritius, 

 and also on account of the widely separated habitats of the two 

 forms, I was at first inclined to regard the species as distinct. 

 Before, however, applying a new specific name to the specimen from 

 the Mauritius, I submitted a sketch of the chelipede and cephalo- 

 thorax to Prof. A. Milne-Edwards, who very kindly compared them 

 with the type of P. longimnnus in the Paris collection, and sent me 

 the following observations, with an outline drawing of the Paris 

 type :— 



" he Palinvrus lonffimanus (M.-Edwards) ressemble beaucoup a 

 I'espece qui a ete trouvee au voisinage de I'ile Maurice et dont vous 

 m'envoyez un croquis. II y a cependnnt quelques legeres differences 

 dans la disposition des epines. Vous pouvez en jnger par le dessin 

 ou j'ai figure la carapace du P. longimamis type de notre collection. 

 En arriere de I'epine laterale postorbitaire il s'en trouve une seconde 

 qui me parait manquer sur I'exemplaire de Maurice. Le doigt 

 de la main du Palinurus du Museum de Paris est moins courbe, mais 

 la forme du membre est bien la meme. Ce sont, comme vous 

 voyez, de bien petits differences.'' 



These remarks and the figures so courteously sent leave no doubt 

 in my mind as to the specific identity of the two forms. The 

 spine behind the lateral postorbital spine, which was not represented 

 in the sketch sent to M. Milne-Edwards, is distinctly developed on 

 one (the left) side only of the Mauritius specimen, where, however, 

 it is very small. 



As no sufficient description or accurate figure has as yet appeared 

 of this Palinurus, which is certainly one of the most remarkable de- 

 scribed, those which are now given will not be without interest ; and 

 the minor distinctions i-eferred to below will, I think, justify me in 

 considering the Mauritius specimen as belonging to a distinct variety 

 — the more so as this is, I believe, the first recoided instance of a 

 Crustacean from the Mascarene subregion being specifically identical 

 with one from the West Indies, unless, indeed, certain species having 

 an almost cosmopolitan distribution are to be excepted. This, more- 

 over, is in itself a fact of much interest on acconnt of the well-known 

 affinities that exist between the INIascarene and South- American 

 faunas. 



Whetlier P. longimanus is to be regarded as an instance of a once 

 (videly-spread species surviving to the present period in these widely 

 distant and isolated localities, or whether further researches will de- 

 monstrate its existence at Cape Verd or on the western coast of 

 Africa (whence it may have passed round the Cape of Good Hope 

 into the Oriental region), time only will show. Certain it is that it 

 differs widely from the typical Palinuri in the remarkable develop- 

 ment and dilated palms of the anterior legs, which may be taken 

 by some zoologists as indicative of an affinity with the Astacina. 



