SINCLAIR : TYPOTHERIA OF THE SANTA CRUZ BEDS. 
13 
descriptions and figures and from such photographs of the type speci- 
mens as the writer has examined, they seem to be referable to the same 
suborder as the forms described in this memoir. 
CONCLUSIONS. 
The present investigation demonstrates, in the writer’s opinion, that the 
Typotheria are to be regarded as a suborder of the Toxodontia, differing 
from the suborder Toxodonta, to which Nesodon, Toxodon and their allies 
are referable, in the more primitive structure of the teeth and feet. The 
origin of the group is entirely unknown, but was probably in South 
America. No complete phyletic series can be traced from its first appear- 
ance in the Notostylops beds to its disappearance in the Pampean. The 
Santa Cruz Typotheria are not ancestral to Typotkerium. No rodent 
or hyracoid affinities can be claimed for them. 
SYNONYMY. 
In working out the synonymy adopted in the systematic part of this 
memoir the writer has depended largely on a series of photographs of the 
type specimens taken by Professor W. B. Scott and on the measurements 
given in Dr. Ameghino’s published descriptions. The specimens in the 
collection of the Akademie der Wissenschaften at Munich are accom- 
panied by Dr. Ameghino’s manuscript labels and are practically cotypes. 
A large number of species which could not be identified with any of the 
material in the collections studied have been listed, at the end of the 
present memoir, as Typotheria Incertae Sedis, but, as there explained, it 
does not follow that these are all invalid. 
INTERA THERIID Ad. 
PROTYPOTHERIUM Ameghino. 
(Plates III; IV; V; VI, Figs. 1-10, 14, 15 ; VII; Text Figs. 1 A, 2, 3 A, 4 A, 5 A, 6 A, 8, 9.) 
Protypotherium Amegh.; Catalogo de la provincia de Buenos Aires en la 
Exposicion Continentale Sud-amer., March, 1882 ( nomen nudum ') ; 
Observaciones generales sobre el orden de mamiferos estinguidos 
sud-americanos llamados Toxodontes (Toxodontia), etc., p. 52, 1887 1 
Enum. Sistematica, etc., p. 15, 1887. 
