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Show 1904.] ON NEW FISHES FROM THE NIGER. 197 artery to arise from the basilar behind the sixth nerve. I have noted as exceptions only Tragidus meminna and Gazella ruhfrons, which in this point agree with Man*. (4) The cix-cle of Willis is generally, but not always, entirely symmetrical ixx itself and in its branches. When it is incomplete, as e. g. Hyrax (posteriorly) and Lagostomus (anteriorly), or asymmetrical (e. g. ophthalmic artery in Myopotamus), the advantage lies with tlxe left side. (5) A rete is occasionally (e. g. Tamandua) formed between the circle of Willis posteriorly and the pituitary body in front. (6) The brain of Hyrax has an arterial system constructed upon the Ungulate plan, axxd is especially like tlxe Horse. (7) Tamandita shows charactex-s which are elsewhere found in the Carnivoi-a in respect of the rhomboidal area surrounded by equisized vertebral and antex-iox- spinal artex-ies. (8) The Arctoid Carnivora can apparently be distinguished from the JEluroid Carnivox-a by the mode of origin of the callosal arteries. In the fox-mer they arise nearer to the circle of Willis and fuse to form a single artery. In the latter the artex-ies are given off later and do not fuse; but there is a communicating artery which joins the two cerebx-als before they give off the callosal. It is clear, therefore, that the cix-cle of Willis may be completed anteriorly by arteries which are not homologous. 'A. Descriptions of Three new Fishes discovered by the late Mr. J. S. Budgett in the Niger f. By G. A. B O U L E N G E R, F.R.S., V.P.Z.S. [Received December 17, 1903.] (Plates VII. & VIII.J) MARCUSENIUS BUDGETTI. (Plate VII. fig. 1.) Depth of body 3 times in total length, length of head 5 times. Head a little deeper than long ; snout rounded, i length of head ; mouth small, inferior, its width 4 length of head ; teeth small, notched, 5 in the upper jaw, 6 irr the lower ; anterior nostril on a line with the lower border of the pupil and equally distant from * I do not suggest at present that this is an Ungulate character since my material is obviously too scanty. Hyra.v does not agree with Tragidus and Gazella. f This note was intended to supplement an account by Mr. Budgett of his expedition to the Niger in quest of the ega:s of Polypterus, which was to have been read before this Society at the January meeting. In the meantime Science has had to deplore the loss of this gifted and courageous zoologist, who died on Jan. 19, on the very evening his paper was announced for reading, from fever contracted on his expedition.-G. A. B. X For explanation of the Plates, see p. 199. |