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Show 376 DR. ST. G. MIVART ON THE ARCTOIDEA. [Apr. 21, external cingulum. Two other cusps are developed from the internal cingulum. The fourth lower premolar has one principal cusp, with a very small one in front of it and two large ones behind it. The first lower true molar has two external cusps in front; the hinder one predominates greatly. There is also an internal cusp (less developed than in Helictis), and a distinct talon with three small cusps. The second lower true molar has three small external cusps and one large internal cusp. The brain *• has a long, oblique, Sylvian fissure ; the Sylvian gyrus is much narrower in front than behind. The parietal gyrus is simple. The sagittal gyrus is wide, especially towards its anterior end. There is a distinct but small Ursine lozenge and calloso-marginal and crucial sulci join. The parietal and sagittal gyri unite posteriorly, as they do in Helictis. Galictis2.-The Tayra has the digits closely connected, the soles naked, and the gait almost plantigrade. The nose has a median groove. The ears are short and rounded. The pupils are round. The concha is small and flat, with a very shallow pouch, and then superimposed transverse ridges. The Tayra ranges from the Rio de la Plata northwards to Mexico. It is more or less gregarious, that is to say it has been observed in troops of from 15 to 20 individuals sometimes, at least in British Honduras. There are 14 dorsal, 6 lumbar, 3 sacral, and 23 caudal vertebrae. The neck is relatively long, longer than in almost all other Arctoids. The first and second lower true molars are at almost their minimum length amongst Arctoids, compared with the length of the skull. The scapula has a very distinct and well-developed metacromion. Both hallux and pollex are fairly developed. The skull has a sagittal ridge and its zygomata are rather strongly arched outwards. The bulla is like that of Meles, with its ridge more rounded. The glenoid foramen is large and opposite the middle of the postglenoid process. The paroccipital process is but little prominent and is applied to the back of the bulla. The mastoid process is rounded, so as to be little conspicuous. It does not depend below the meatus. The muzzle is short. There are frontal sinuses. The palate is wide and extends backwards beyond the last molars much as it does in Meles. There is a small postorbital process developed from the malar and a pretty good one from the frontal. The infraorbital foramen is moderate. The meatus auditorius externus is short and of moderate capacity. The angle of the mandible is pressed up very near to the condyle, and the margin 1 L. o. p. 18. 2 See Linn. Syst, Nat. (1766) i. p. 67; Schreb. iii. p. 493; Desm. Mamm. p. 175*; Rengger's Paraguay, p. 119; Traill, Mem. of the Werner. Soc. iii. p. 440, pi. 23. Tayra, Buffon, Suppl. vii. p. 250, pi. 60 ; Azar. Ess. i. p. 197; Fr. Cuv. Mamm. iii.; Wagner, Suppl. ii. p. 214; Biologia, p. 79; Bell, Zool. Journ. ii. (1826) p. 552; Frantzius, Arch. f. Naturg. xxxv. 1, p. 287; Moore P. Z. S. 1859, p. 51 ; P. Gervais, M a m m . ii. p. 110; Gray, P. Z. S. 1865, p. 121 ; De Blainville, Osteog. Mustela; Cat. Carnivora Brit. Mus. p. 99; Tschudi, Fauna Peruana & Arch. 1841, p. 248 ; Hernandez, vol. vii. cap. 21, the Tapeytz-cuitli. |