4© PATAGONIAN EXPEDITIONS: PALEONTOLOGY. 



Localities. — The type-specimen was found in "the cliffs of the Santa 

 Cruz River"; No. 15,295 was collected by Mr. Peterson on the coast of 

 Patagonia, ten miles south of Coy Inlet. The field label says: "base of 

 Santa Cruz beds." 



LICAPHRIUM Ameghino. 



(Plates VI ; VII, Figs. 1-7^.) 



Licaphrium Amegh.; Enum. sistematica, etc., 1887, p. 20. 

 Anisolophus Mercerat, in part; Rev. del Museo de La Plata, T. I, 1891, 

 p. 462. 



There may be some doubt as to the propriety of separating this genus 

 from Proterotheritim, for, although typical specimens of the two are quite 

 strikingly different, transitions between them are not wanting. Yet, as 

 there is no certainty that these transitional forms are all strictly contem- 

 poraneous, it would serve no useful purpose to unite the two genera. 

 LicapJirittm maybe distinguished by the following characteristics: (i) 

 The animal is relatively heavier and more robust and the teeth are more 

 massive than in Proterotheriiim. (2) The internal ridge of p- is not 

 divided into cusps, while p- and p- have no tetartocone. (3) In the 

 upper molars the two internal cusps are less distinctly separated and in 

 m- they are actually connected by an enamel ridge ; in m- the hinder 

 half of the crown is less reduced and in some of the species there is a 

 small, but distinct hypocone. (4) In the lower jaw, the molariform pre- 

 molars and the molars have shallower and less defined valleys and in the 

 molars the postero-internal pillar is much larger than in Proterotheritmt, 

 while the talon of nis is not so clearly separated from the posterior cres- 

 cent. (6) The limb bones are heavier and the feet shorter and thicker. 



Dentition (Pis. VI, figs. \a, ib, 3-5 ; VII, figs. 2-7^). 



Upper Jaw. The incisor has the same caniniform, tusk-like shape as in 

 Diadiaphorns and Proterotheriiim. Of p- I have seen no unworn speci- 

 mens ; when well abraded, it resembles that of Proterotheriiim, while p-2- 

 differs from the type usual in the latter genus in not having the internal 

 ridge divided into two cusps. The third and fourth premolars, though 

 nearly molariform, differ somewhat from each other ; p- is smaller, has 

 much smaller conules, less prominent anterior and posterior cingulum, 

 and a minute, incipient tetartocone, which is absent in p-. Both of these 

 teeth are thus distinctly less advanced in differentiation than those oi Pro- 



