I5O PATAGONIAN EXPEDITIONS I PALAEONTOLOGY. 



The teeth (Plate XXIV, figs. 10, 11) are remarkable for the simplicity 

 of those in the anterior part of the mouth. In the upper jaw, -, -, and * 

 are of longitudinally elliptical form and have no complications of any kind, 

 the others are all relatively broad ; on the last four teeth, -'*-, the division 

 of the postero-external lobe is very feebly, or not at all indicated, while 

 the division of the anterior prism into internal and external lobes is very 

 distinct. In the mandible, T, ?, and ^ have successively larger grinding 

 surfaces, of reniform shape with the concavity turned outward ; T is of 

 similar general form, but obscurely trilobate, while F- are typically so. 



The skull is very large, but those of the Ameghino collection were, at 

 the time of my visit, so concealed in the matrix that no description of 

 them can be given, other than to note the relatively great length of the 

 rostrum. Ameghino in his original description gives the length of the 

 skull as 1 80 mm. 



The following measurements are approximate only, as they are taken 

 from photographs of the type specimen in the Ameghino collection. 



MEASUREMENTS. 



Cephalic shield, length 135 &, width 0095 



" " width 138 Lower dentition, length 113 



Upper dentition, length no T , length 0065 



J-, length (i. e., antero-posterior diam- " width 0035 



eter) 006 ^, length 007 



" width (i. e., transverse diameter) 0045 " width 005 



A, length 007 s , length oil 



" width 006 " width 007 



, length 009 f, length 014 



" width 006 " width 007 



A, length on -%, length 015 



" width 009 " width 005 5 



5., length 013 ^, length 0145 



" width 009 " width 007 



1, length 015 T , length 014 



" width 009 " width 0065 



i, length 014 -g, length 016 



" width oio " width 0065 



S-, length 015 



EUCINEPELTUS coMPLiCATUS Brown. 



(Plates XXI, Fig. 3; XXIV, Fig. 9; XXIX, Figs. 1-5.) 



Eucinepeltus complicatus Brown; Bull. Am. Mus. Nat. Hist., Vol. XIX, 

 1903, P- 453- 



