422 PATAGONIAN EXPEDITIONS I PALAEONTOLOGY. 



Mj, antero-posterior diameter ......... .001 



" transverse " 0008 



Depth of mandible below median premolar ...... .0022 



" M T .0023 



" " " " M T 0022 



GARZONIA Ameghino. 



(Plate LXIII, Figs. 8, Sa, 10-13.) 



Garzonia Amegh. ; Nuevos Restos Mamif. F6s. Patagonia Austral, pp. 

 21-22, Aug., 1891 ; Revista Argentina, I, entr. 5^, pp. 307-308, Oct., 

 1891. 

 Phonocdromus Amegh. ; 6num. Syn., pp. 99-100, 1894. 



The genus Garzonia is represented in the Princeton collection by the 

 left half of a lower jaw (No. 15,238), associated with parts of both fore 

 limbs, referred provisionally to G. patagonica. 



Dentition (PI. LXIII, figs. 8, Sa). The tip of the median incisor has 

 been broken off, but enough remains to show that the enamel is confined 

 almost entirely to the outer side of the crown. Six single-rooted, more 

 or less pronate, vestigial teeth follow the enlarged incisor. Of these 

 the first, fourth, fifth and sixth are preserved. The second and third are 

 represented by roots retained in the alveoli. The antemolar formula of 

 this individual is therefore nine, the highest on record among the Dipro- 

 todontia. The constancy of this character may well be doubted. The 

 median premolar and parts of both walls of its alveolus have been broken 

 away, but enough remains to show the double-rooted character of the tooth. 

 The posterior premolar is a large tooth supported on heavy roots, with the 

 crown laterally compressed and, in some species (Garzonia typicd], elevated 

 considerably above the molar series. In No. 15,238, the enamel has been 

 broken from the tip of the crown, which probably had a slightly greater 

 degree of elevation than is indicated in the figure. The rather prominent 

 heel of the posterior premolar is overhung by the anterior portion of M T . 

 The molars are greatly worn, and the crown pattern, which appears to have 

 been similar to that in Ccznolestes, almost obliterated (cf. PI. LXIII, figs. 

 Sa, I4<5). The last molar is single-rooted, a character which distinguishes 

 Garzonia from Hahnarhipus and Ccznolestes. The crown has been broken 

 off. In MT the trigonid is somewhat higher than the talonid, as in Cczno- 

 lestes. This was probably true also for M^ and M^, but has been obliter- 



