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 Heliclis), 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 pos- 

 teriorly, as they do in Helictis. 



Gaiictis'. — 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. Tlie 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. Tlie 

 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 audi- 

 torius 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. 0. p. 18. 



^ See Linn. Syst. ISat. (1766) i. p. 67 ; Schreb. iii. p. 493 ; Desm. Mamm. 

 p. 175*; Eengger's Paraguay, p. 119; Traill, Meiu. of the Werner. Soc. iii. 

 p. 440, pi. 23. Tayra, Buffon, Suppl. yii. p. 250, pi. 60 ; Azar. Ess. i. p. 197; 

 Fr. Cut. Manim. 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. GervaLs, Mamiu. ii. p. 110 ; Gray, P. Z. S. 1865, p. 121 ; 

 De Blain^ille, Osteog. Mu^tela ; Cat. Carnivora Brit. Mus. p. 99; Tsi-hudi, 

 Fauna Peruana & Arch. 1844, p. 248 ; Hernandez, vol. vii. cap. 21, the Tapeytz- 

 cuitli. 



