CHAPTER iXi1 
PROBOSCIDEA 
Suborder Pyrotheria 
Tuts suborder was established by Ameghino to receive 
the peculiar genus Pyrotherium and related forms. These 
animals are of large size, massive build, with narrow 
elongated skulls, in which the nasal opening is situated 
far back, as in animals with a proboscis; with a tiny brain 
case surrounded by cellular spaces; with the maxillae, 
palatines, pterygoids and alispenoids developed downward, 
so that the palatal plane makes a strong angle with the 
basi-cranial plane; and with the occipital condyles high 
up on the back of the skull. Then the first and second 
upper incisors and the second lower incisors are developed 
into enormous tushes with enamel on the anterior sides only. 
The remaining incisors, the canines, upper premolar 1, 
and lower premolars I and 2 are wanting; the remaining 
premolars and the molars being developed into great 
quadrilateral grinders, each with two transverse crests. 
The neck is short, the limbs massive and short, especially 
the lower members of each limb, and the feet were probably 
five-toed. 
The relationship of these forms has been the subject 
of extended discussion: Ameghino seeing in this genus 
the ancestors of the Probiscidea, and comparing them with 
Palaeomastodon, Dinotherium and Barytherium, even finding 
resemblances to Diprotodon; Gaudry concludes that they 
are not proboscidians; and others have suggested that 
they were specialized toxodonts. I have prepared the 
following table of comparisons with Palaeomastodon, a 
toxodont, and Dziprotodon. 
