1897.] Paleontology. 979 
The Paras reached a large size and became extinct at the 
end of the 
The nee caudate of the rachitomous condition is seen in Cri- 
cotus Cope. Each vertebra consists of two fully ossified elements. The 
centra in the precaudal region completely support the neural arches, 
which have well-developed diapophyses. These diapophyses are placed 
on the neurocentral suture which is, however, completely obliterated. 
The centra are 15 mm. long, 25 mm. broad, and 25 mm. high; they are 
very deeply biconcave and notochordal. In front of this centrum is a 
complete intercentral disc, of the same breadth and heighth as the cen- 
trum, but only 8 mm. long; laterally at the posterior border it posses- 
ses a small process to which the capitulum of the rib is articulated. 
These flat intercentral discs have a very large notochordal foramen (4 
mm, in diameter). In the tail the intercentral discs carry the 
chevrons. This condition has been called by Cope embolomerous and 
the suborder Embolomeri. It is evident that the centra are homologous 
to the pleurocentra. The Embolomeri became extinct in the Permian. 
Only two genera are known, Cricotus Cope and Diplovertebron, From 
the Rachitomi the Amniota developed. The pleurocentra formed the 
centra, and the intercentra were more and more reduced, Intercentra 
are present between all the vertebre in the Pareiasauria (Cotylosauria) 
Pelycosauria, Rhynchocephalia, Geckonidx, Uroplatide. In the Ich- 
thyosauria, and Lacertilia they are confined to the anterior cervical 
vertebra. In the Megalosauria, Iguanodontia, Pterosauria and Birds; 
the first intercentrum forms the lower piece of the atlas ring, and the 
second intercentrum is united with the centrum of the atlas (odontoid 
process) and the centre of the axis into one mass. In all mammals the 
first intercentrum always remains, forming the lower piece of the atlas 
ring, and in some mammals they are even present in the dorso-lumbo- 
sacral region, for instance in the Insectivora (Talpa, Erinaceus, Myo- 
gale) and in Atherura among the Rodents.” 
T gave in 1886 a full historical account of the views on the 
morphogeny of the vertebral column of the Amniota from 1844, giving 
all the morphological, paleontological and embryological evidence.” 
Dr. Gadow certainly did not study this paper, for, after the quotation 
of it in his Literature, he puts in parenthesis “ Extract, in German, of 
Cope’s discoveries.” 
n Baur, G., L. C, 
1? Baur, G. Uber pty Morphogenie der Wirbelsäule der Amniolen. Biolog. 
Centralbl. Band VI, Nr. 11 and Nr. 12, Aug. 15, 1886, p. 322-342; 353-363. 
