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Show 1885.] DR. ST. G. MIVART ON THE ARCTOIDEA. 393 a doubtful problem. It has the number of true molar teeth external form of the Bears, but it is less plantigrade. The condyloid foramina are minute instead of very large, and the basiocci-pital has the depressions separated by a crest, as in the Badgers, instead of being flat and wide, as in the Bears ; and the bulla, instead of being wide and flattened, is slightly swollen out, but very small, as in Ailurus. Then there is no alisphenoid canal; while the glenoid foramen, so conspicuous in the Bears, is hidden at the bottom of a large notch between the bulla and the zygoma. The general form of the mandible also is much more like that of Ailurus than of Ursus. There is a fundamental resemblance also between the crowns of the teeth in Ailurus and Ailuropus, in spite of their exaggerated character in the latter genus ; so that on the whole it appears to me that there is a more decided natural affinity between Ailuropus and Ailurus than between Ailuropus and Ursus. The Weasels and their allies seem to be specially predacious variations of the Badger type ; and I have no reason to urge (beyond the structure of the kidney) against the generally received view that the Otters are aquatic variations of the same type. There will thus be three families, P R O C Y O N I D A , MUSTELIDA, and URSID^E. The first of these is plainly subdivisible into two subfamilies-( 1) Procyonina, and (2) Ailurina; while I agree with Professor Flower in dividing the MUSTELID^E into the three subfamilies-( 1) Melina, (2) Mustelina, and (3) Lutrina. These subdivisions may be synoptically characterized as follows :- Fam. I. PROCYONIDA. Kidneys simple. True molars s or g, obtusely tuberculated. Dentition not sectorial. Alisphenoid canal present or absent. Hab. America or Asia. Subfamily 1. PROCYONIN.<*E. True molars g. No alisphenoid canal. Molars not very complexly tuberculated. Hab. America. Procyon. Bassaris. Cercoleptes. Nasua. Bassaricyon. Subfamily 2. AILURINA. True molars \ with an alisphenoid canal, or § without an alisphenoid canal. Molars very complexly tuberculate. Hab. Eastern Asia. Ailurus. Ailuropus. Fam. II. MUSTELIDiE. Kidneys mostly simple. True molars \ or T. Teeth tuberculate or sectorial. No alisphenoid canal. Hab. Old and New Worlds. |