1878. | Geology and Paleontology. 407 
papers Prof. Marsh has had the opportunity of seeing. Two fur- 
ther notices of the vertebrates of the American Permian appeared 
on April 22d of the present year, in the May number of this 
journal, pp. 319, 327. As the corresponding number of the Amer. 
Jour. Sct. and Arts was not issued before May 5th (perhaps a 
day or two sooner), Prof. Marsh had the opportunity of seeing 
these also. They include references to seven new genera, for 
most of which the characters are clearly pointed out. 
The features common to the genera of the Permian, described _ 
by Marsh, are stated by him to be those characteristic of the 
order Rhynchocephalia; as I have already shown to be the case 
with the forms described by me in the earliest as well as later 
papers of those cited. Another characteristic is said to be the 
presence of the intercentrum, a statement agreeing with my own 
in the May number of this journal. It is also observed that there 
is a double tubercular rib-articulation of the centra, a structure I 
have already described in the genus Diplocaudus Prof. Marsh’s 
Statement that the mode of implantation of the teeth is similar 
to that of the “ Mosasuria” is probably incorrect. 
As the author of the paper does not think it necessary to 
allude to published sources of information, it is too much to 
expect him to give credit for ideas communicated to him verbally. 
All of the above mentioned, and additional characters cited by 
Marsh in his two opening paragraphs? (l.c. 409) as belonging to 
the Permian Reptiles, with others, were explained by me before 
the National Academy of Sciences, with Prof. Marsh as an atten- 
tive listener, at its last meeting in Washington, April 18th, more 
than two weeks before the appearance of the paper here criti- 
cized. The characters to, which I refer are “the separate pre- 
_? Proceed. Amer. Philos. Soc. 1877, p. 187. 
* Except that mentioned previously under Diplocautus. a 
i 3 Which I referred to the Rhynchocephalia in 1870; see Proceed. Am. Ass. Adv. — 
Sci. xix, p. 242. we ee 
