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Show 88 DR. ST. GEORGE MIVART ON THE GENUS CYON. [Feb. 18, 3. Notes on the Genus Cyon. By ST. G E O R G E MIVART, F.R.S. [Eeceived February 1, 1890.] Through the kindness of the authorities in charge of the Zoological Collection in our National Museum, I have been enabled to make as careful an examination as I could of the numerous specimens (skins and skulls) of the above-named interesting genus which are therein preserved. Amongst the skulls I find one, No. 58. 5. 4. 99, which came from the collection of this Society, and which presents the singular anomaly of having no trace of the second upper molar on either side. With this exception, all the skulls examined by me agree in possessing the following characters, most of which I have not found to have been as yet noted :- Nasal bones extending backwards much beyond the adjacent portions of the maxillae; the external margin of each nasal, distad of the nasal process of the frontal, strongly concave, so that the outer margin of the whole length of each nasal has a subsigmoid outline. Face relatively short; dorsal surface of interorbital region but little concave transversely ; skull viewed in profile showing very little vertical elevation of the interorbital region, the concavity thus apparent between it and the distal end of the nasals being very slight both in degree and in antero-posterior extent ; postorbital processes of the frontal projecting outwards but slightly ; postorbital processes of the malar rather marked ; zygomata not strongly arched outwards ; anterior palatine foramina very large and much elongated. First upper premolar approaching the second in sizs more nearly than in Canis ; fourth upper premolar with a smaller internal lobe ; inner portion of first upper molar relatively smaller, its inner tubercles and cingulum having more or less completely coalesced ; first lower molar relatively smaller, especially its inner ridge. Tail decidedly less than half the length of the body. I have been unable to satisfy myself that more than two species of this genus can be distinguished, and it seems to me possible that even this distinction may be found unsatisfactory when more skulls are obtained from Northern Asia. The North-Asiatic species C. alpinus of Pallas : is represented by two skins which differ slightly in colour. One from Siberia is very white; the other, which has a yellow tinge, conies from the Altai, and its skull is in the collection 2. It differs from all the other skulls in the large size of its second upper molar (as has been previously recorded) and also in the large size of the second (and last) lower molar, and in the less massive form of the angle of the mandible. 1 Zoogr. Rosso-Asiat. i. p. 34. 2 It is that marked No. IX. in Prof. Huxley's table of measurements, P. Z S 1880, p. 275. |