Cope.] 82 [July 20, 
tainly have been much better if he had first given himself a little practice 
in the manipulation of acoustic instruments, before having treated so 
slightingly the results obtained by Lissajous, by Despretz, by Helmholtz, 
by Mayer, etc., etc., and before seeking to throw discredit upon the labors 
of a constructeur who had no reason to expect so unjustifiable an attack. 
In addition to Helmholtz’s evidence, Professor A. M. Mayer has furn- 
ished the following statement concerning the absolute number of vibra- 
tions of Kénig’s forks. ‘‘ During the months of March, April and May of 
1876, I made many determinations of the number of vibrations of Konig’s 
UT, fork and found that it gave 255.96 complete vibrations in one second 
at a temperature of 60° Fahr. The following are the separate determina- 
tions of that series of which the above number is the mean: (1) 255.95, 
(2) 255.97, (8) 255.90, (4) 255.92, (5) 256.02, (6) 256.02. The forks vibra- 
tory period is accelerated or diminished 533,55 part by a difference of tem- 
perature of +1° Fahr.”’ 
26 Rue de Pontoise, Paris, June 5th, 1877. 
On a New Species of Adocide from the Tertiary of Georgia. 
By E. D. Cope. 
(Read before the American Philosophical Society, July 20, 1877.) 
Professor George Little, State Geologist of Georgia, placed in my hands 
for determination a Chelonite from a Tertiary formation in Macon Co. of 
that State. The matrix is a rather soft limestone of a light drab color. 
When the specimen was first obtained it was nearly perfect, lacking only 
the posterior part of one side, and the posterior border of the carapace. 
Having been mutilated by destructive curiosity hunters, there remain now 
the plastron and the anterior half of the carapace, with a considerable por- 
tion of the posterior part of the left margin. The surface has been exposed 
to the weather so as to obscure, and in some places to obliterate the dermal 
sutures, while the skeletal sutures are distinct. The form has been slightly 
distorted by lateral pressure, but not much. 
The obscurity of the dermal sutures renders the determination of the ge- 
neric affinities somewhat difficult. The skeleton preserves the Emydoid 
type, not exhibiting intersternal bones, and having a well developed me- 
sosternum. ‘The vertebral bones extend to between the sixth pair of cos- 
tals, beyond which the specimen is imperfect in that region. The costal 
capitula are well developed, but whether they reach the vertebral centra, 
the specimen does not permit me to discover. The plastron is of peculiar 
form, the lobes being short and contracted. The anterior is rounded from 
a base of usual width, while the posterior, from a similar base, narrows 
rapidly to a point, as in the genus Aromochelys. 
An important point is observed in the direction of the abdomino-pectoral 
