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Show 1903.] OX ABNORMAL CLAWS IN THE CRAB AND LOBSTER. 195 near Lado, on the White Nile, which, by the owner's kind permission, I exhibited at a meeting of this Society on Dec. 18th, 1900 (see P. Z. S. 1900, p. 949). Its identity had been previously established by Mr. Thomas, who had recorded its occurrence in ' Nature' of Oct. 19th of that year ('Nature,' vol. Ixii. p. 599). This skull is now, I am informed, in the Carnegie Museum at Pittsburg, U.S.A. The horn of an example of the same species, which I now exhibit, was obtained by m y friend Capt. Claude Hawker (Commander of the 10th Soudanese Battalion) from the Belgian Officers at Lado in the autumn of 1902, and was taken from a specimen unquestionably shot in that district, on the left bank of the While Nile. The Belgians did not distinguish it from the ordinary R. bicornis, and seemed to believe that all the Rhinoceroses of that district belong to one species. " The present specimen is a front horn of R. simus, or, at any rate, of a closely allied form. It agrees very well with the front horn of the mounted specimen of R. simus in the gallery of the British Museum, but is rather longer, measuring 31 inches in a straight line from the base to the end. The front horn of R. simus may always be distinguished from the corresponding horn of R. bicornis by its broad, flattened surface at the base in front, the basal front of this horn in R. bicornis being more or less smooth and rounded and projecting in the centre. " Capt. Hawker has returned to the Soudan, and will probably visit the southernmost station of the Anglo-Egyptian forces at Mongalla, 15 miles north of Gondokoro, again this winter. I have requested him to obtain further information about this Rhinoceros, and have little doubt that he will do so." The Secretary exhibited a series of photographs of the Indian Elephant in the act of congress, which had been presented to the Society by Mr. H . Slade, of Rangoon, Burma. Mr. Henry Scherren, F.Z.S., exhibited some specimens of the Edible Crab {Cancer pagurus) and the Lobster {Astacus gammarus) showing meristic variations, and made the following remarks:- " Both these variations are in the left chela. That of the Crab I received from Mr. Arthur Patterson of Yarmouth, in whose name it will be handed over to the British Museum (Natural History). A process grows from the lower edge of the palm, resembling, though not very closely, the fixed and movable fingers. It is, I suggest, a case of a rudimentary extra pair of fingers, of which many examples have been figured by Bateson. The variation in the Lobster, also in the left chela, is more complex. There is a process growing from the upper edge of the mero-podite, having three spines round the anterior margin, and a soft articular membrane arising therefrom. Beyond this is a three-pointed process-a duplicate carpopodite, which must have been movable in the living animal. On the normal meropodite, 13* |
