E. LÖNNBERG, MAMMALOGY OF ECUADOR. 47 



If the skulls of the Pacas from Gualea are compared 

 with those of Brazilian Pacas, it is easily seen that the 

 parietal region of the former is comparatively sborter tban 

 that of the latter. This can be expressed in the foUowing 

 way: the parietal measured mesially, with occipital örest 

 included, is inthe former only 63 (^y to 64,7 % (J") of the 

 mesial length of the frontal, but in the latter 70.7 (J*) to 

 77 % (?). How this condition is in virgnia, I do not know. 



The anterior portion of the frontals and the posterior 

 parts of the nasals are in the Brazilian Paca quite flat, but 

 in the Gualea form somewhat raised or inflated. As a con- 

 sequence of this the sulcus from the upper anterior corner 

 of the orbit which runs forward above the foramen infra- 

 orbitale and över the premaxillary, is more curved in its 

 posterior portion and runs in its anterior portion at a lower 

 level compared with the upper surface of the skull in the 

 adult Paca from Gualea than in the Brazilian one. In the 

 latter the posterior course of this sulcus is more straight 

 and its position all the time nearer the top level of the skull. 

 As the young Paca from Gualea presents similar conditions 

 with regard to this sulcus as the adult Brazilian ones, the 

 latter evidently have retained a primitive character in this 

 respect, and they resemble at the same time the alpine Pacas 

 in this characteristic. 



The Pacas from Gualea and Brazil resemble each other 

 with regard to the shape of the antemolar or diastema por- 

 tion of the palate, because the raised crests of the maxilla- 

 ries and the premaxillaries, which börder the palatal fossa, 

 are quite, parallell even behind. The same condition is also 

 found in Coelogenys sierrae Thomas. On the other hand 

 Stolzmann's figure of the skull of C. taczanowskii proves 

 that the crests of the maxillary converge behind, so that 

 the palate fossa becomes narrowly V-shaped, and the same 

 condition also prevails in my C. s. andina. 



The three former also agree in another small detail. They 

 have a groove on the frontal at the base of the postorbital 

 process, which in adult specimens is rather deep and well 

 marked. In the two latter again there is a quite shallow 

 groove a little further forward and inward, but not just at 

 the root of the postorbital process. 



^ Even in the young. 



