610 General Notes. | August, 
Prof. Cope, in the Proceedings of the American Philosophical 
Society for May, 1880 (Palzontological Bulletin, No. 32), enters 
into the structure of the genera Eryops and Trimerorhachis, and 
re-defines the sub-order Ganocephala, showing that it differs 
materially from other Stegocephah in the structure of the verte- 
bral column 
The present occasion is a convenient one for a further addition 
to the subject, which chiefly concerns the genus Cricotus. This 
remarkable form has been characterized in this journal? and else- 
where? by the complete development of its centra and intercentra, 
both of which form entire vertebral bodies and in pairs support sin- 
gle neural arches. No such character has been detected in the 
known divisions of the Stegocephali, but before establishing a new 
one for it, I have waited further information. Additional knowledge 
of its structure shows that it is the type of a distintinct division 
of the Stegocephal, which may be defined as follows: 
Centra and intercentra subequally developed as vertebral bodies, 
a single neural arch supported by one of each, forming a double 
body. evron bones supported only by intercentra. Basioccip!- 
tal vertebral articulation cup-like, connected with the first verte- 
bra by an undivided discoid intercentrum. 
Thus the peculiarity of the vertebral column in general is car- 
ried into the cephalic articulation, and we have, instead of the 
complex atlas of the Ganocephala, a single body connecting 
occipital condyle and first vertebra. This body represents, 1n all 
probability, the single occipital condyle of the-Reptilian skull. This 
part, as is well known, remains cartilaginous in the lizara* long after 
the basioccipital is ossified, and is a distinct element. The struc- 
ture of Cricotus shows that it is a connate intercentrum. We 
ave not been derived from the Ladyrinthodontia as has been sug- 
gested, nor from the Ganocephala, but from the Embolomera, as 
I call the new order, or sub-order. The order of Reptilia which 
stands next to it is, of course, the Zicromorpha, which presents 
so many Batrachian characters, including intercentra, as od 
for the first time pointed out in the paper above quoted. Be- 
sides Cricotus, Fritsch describes a genus from Bohemia under the 
name Liplovertebron, which I suspect to belong to the Lmbo- 
lomera.—E. D. Cope. 
Tue GENEALOGY OF THE AMERICAN RHINOCEROSES.— The ee 
Aceratherium has been supposed to be represented in Nort 
1 Cope, Proceedings Academy, Phila., 1875, p. 403. 
2 1778, p. 319, May 22, 
* Proceed. Amer. Philos. Soc., 1878, p. 522. 
*See Parker on the development of the skull of the Lizard, Philos. Trans., Lon- 
don, 1979. i 
