1878. ] 337 (Ginley. 
In Testudo carolina it is seale-like with the posterior a flattened rod, and 
the anterior portion far from the jugal. 
There is nothing peculiar in the adult, but in the young the columella is 
small and slender, and in position and shape resembles that of a half-grown 
Chelonia mydas. 
The stapes (sometimes called columella auris) in most birds, reptiles and 
amphibians, is a very slender rod with a disc at one end. The disc end is 
attached to the fenestra ovalis, while the external end is attached to the 
tympanic membrane.* The bone inclines forward at a decided angle. To 
reach the membrane it passes through a canal, or foramen, made by the 
folding in of the posterior part of the quadrate bone. The folding in is 
more complete in adult specimens, and the foramen near the front of the 
tympanic cavity. 
In Chelonia mydas the canal is unusually open, and the stapes on one 
side only protected by muscles. 
In A. spinifer, Ch. serpentina and Macrochelys lacertina, the stapes is 
completely surrounded by bone, the edges of the quadrate being sutured 
together, so as to form a foramen. 
The edges touch in H. odoratus, but do not form a suture. 
In UM. palustris the space is open, but the edges of the quadrate approach 
quite near each other. This isa common form in the emydes. The excep- 
tions are Ch. tnsculptus, where there is a suture, and Chrysemys picta and 
Chelopus guttata where the edges lap. 
The suture is strongly marked in 7%’. carolina. 
Notice of the Discovery of the position of the Crural Processes in the 
Genus Atrypa. 
By WILLIAM GINLEY. 
(Read before the American Philosophical Society March 1, 1878.) 
It is already well known that, in 1867, Professor R. P. Whitfield, palezeon- 
logist of Albany, New York, announced the discovery of ‘‘a loop connect- 
ing the spiral cones’’ in the genus Aftrypa. 
In the Twentieth Regent’s Report he describes in detail this loop with 
its position and affinities; accompanying his article is a plate showing 
various examples from different localities representing a wide geological 
distribution. 
* Cuvier Ossemens Fossiles IX, p. 355. 
PROC. AMER. PHILOS. soc. xvir. 101, 2P. PRINTED APRIL 29, 1878. 
