70 THE AMERICAN NATURALIST. [VoL. XXXII. 
The Pareiasauria Seeley (Cotylosauria Cope) are undoubtedly 
the most ancient of known Reptilia. The resemblance of these 
forms to the Amphibia demand that they be removed from union 
with the remaining Permian Reptilia in the group Anomodontia 
and considered as the ancestral form from which the Progano- 
sauria have been derived, not the reverse, as suggested by 
Haeckel. The most perfect form of this group known is Pareta- 
saurus bombidens O. The cranial characters in which this form 
resembles the Labyrinthodonta arethus summed up by Seeley (1). 
‘The head shows five Labyrinthodont characters: (1) the form; 
(2) the sculpture of the cranial bones; (3) the arrangement of 
the bones that cover the head; (4) the presence of mucous 
canals between the orbits and nares; (5) the absence of the 
lachrymal bone from the anterior corner of the orbit of the eye.” 
To this evidence may be added the presence of a cleithrum, 
figured by Seeley as an epiclavicle (2). The presence of a 
cleithrum in the Pareiasauria is confirmed by the evidence of 
an isolated scapula belonging to this group from the Texas 
Permian, now in the museum of the University of Chicago. To 
the upper end of this scapula is attached the distal end of an 
element that can only be a cleithrum. 
From the Pareiasauria arose the Proganosauria by a series of 
changes involving the appearance of two fossz in the temporal 
region. The first appeared between the squamosal-parietal and 
the prosquamosal-postorbital, the second and lower between the 
prosquamosal-postorbital and the quadratojugal-jugal. This 
resulted in the formation of two temporal arches, an upper, the 
postorbital, and a lower, the jugal. 
In describing the quadrate of Pareiasaurus, Seeley says (2), 
page 325, “the quadrate bones are vertical, compressed, oblique 
plates, which extend outward and backward. They are five and 
one-half inches high, and in contact throughout with the external 
temporal shield.” A figure of a quadrate is given by the same 
author (3), which he refers “ to Pareiasaurus or a near ally ” ; this 
figure shows the characters mentioned above. The American 
forms of this group show the same form of elongated quadrate. 
In Paleohatteria, one of the earliest of the Proganosauria, We 
find the same elongate quadrate. Changes in other regions of 
