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Show 1882.] CRUSTACEANS FROM MAURITIUS. 539 the figure showed distinct 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 series 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 cephalothorax to Prof. A. Milne-Edwards, who very kindly compared them with the type of P. longimanus in the Paris collection, and sent me the following observations, with an outline drawing of the Paris type :- " Le Palinurus longimanus (M.-Edwards) ressemble beaucoup a l'espece qui a ete trouvee au voisinage de File Maurice et dont vous m'envoyez un croquis. II y a cependant quelques legeres differences dans la disposition des epines. Vous pouvez en juger par le dessin ou j'ai figure la carapace du P. longimanus type de notre collection. En arriere de l'epine laterale postorbitaire il s'en trouve une seconde qui me parait manquer sur l'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.'1 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 certainlv one of the most remarkable de-scribed, those which are now given will not be without interest; and the minor distinctions referred to below will, I think, justify m e in considering the Mauritius specimen as belonging to a distinct variety -the more so as this is, I believe, the first recorded 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, moreover, is in itself a fact of much interest on account of the well-known affinities that exist between the Mascarene and South-American faunas. Whether P. longimanus is to be regarded as an instance of a once ividely-spread species surviving to the present period in these widely distant and isolated localities, or whether further researches will demonstrate 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 development and dilated palms of tbe anterior legs, which may be taken by some zoologists as indicative of an affinity with the Astacina. |
