1878. ] 335 {Monks, 
say nothing. Like Cordaites it has some analogy to the Cycade@, the Coni- 
fers and the Monocotyledonous, the Glumacex. But it is evident from the 
character of its leaves, some of which are narrowed to the point of attach- 
ment, that this species is in relation to the groups of the Tenophyllium, as 
also by its nervation to the Cordaites. 
There is in the stem a peculiar character, which should be remarked. It 
rather appears to have been soft than of hard texture. The bark is so thin 
that by erosion some of the scales and young leaves are left attached to the 
lower surface of the stem as seen in the upper part of Pl. LY, fig. 1. On 
another side large leaves, especially seen upon my specimens, are decur- 
ring at the base along the stem, and seen to join it by a division of its 
borders, or come to it ina more or less open angle of divergence without 
any diminution of their width, and without apparent division in their 
point of union, just as if they were part of the stem. The epidermis of the 
leaves is also thin, its surface reflects the largest nervation buried in the 
texture, which then appears obtuse, distant as in figure 2 of Brongniart, but 
under the epidermis, these primary veins are less discernible, sometimes 
totally unobservable, the intermediate very thin vinelets covering the whole 
surface. 
Habitat. These remarkable specimens, which if they do not throw light 
upon the relation of this plant to those of our time, give at least indication 
of their reference to the family of the Cordaites, have been found and 
communicated by Dr. J. H. Britts, from the Clinton coal of Missouri. 
The Columella and Stapes in some North American Turtles. 
By Sara P. Monks. 
(Read before the American Philosophical Society March 1, 1878.) 
The columella is a small bone found in most reptiles which extends from 
the parietal to the pterygoid, and helps to complete the lateral wall of the 
cranium.* 
In Lacertilia it is a distinct, slender rod ‘‘in close contact with the other 
cranial bones at its extremities only. 
In Testudinata on the other hand it is broad, short and scale-like, and 
closely articulated with other bones.+ 
It varies considerably in the different species and families, and in some 
seems to be wanting. 
In nearly all turtles there is a strongly marked ridge extending forward 
from the quadrate to the top of the skull, and another not so distinct from 
the pterygoid backward to the same point on the top of the skull. 
* See Professor Cope ‘“‘On the Homologies of some of the Cranial Bones of the 
Reptilia, and on the Systematic Arrangement of the Class.” 
+ Proceedings of Association for the Advancement of Science, 1870, Vol. XIX, 
pp. 223, 224, and Professor Huxley’s Anatomy of Vertebrate Animals, 1872, p. 189. 
eo? 
