134 E. C. CASE 
Cope* describing such casts, one from a cotylosaurian reptile, 
Diadectes, from the Permian of Texas, and one from a phytosaur, 
Belodon, from the upper Triassic of Texas, but he neither dis- 
cusses these papers nor reproduces the figures given by Cope. 
This is understandable, as the figures are very poor and difficult 
to interpret and the subject-matter is only distantly related to 
the material of his paper. As the casts figured and deseribed 
by Cope are from forms more nearly related to the one described 
in this paper, the figures are reproduced in line drawings as 
accurately as they may be made out. 
The cranial cavity of Desmatosuchus was completely cleared 
out, leaving the surface of the bone in good condition with all 
the pits and foramina clearly marked. As may be seen in the 
figures, the cast as finally secured shows the general form and 
proportions of the brain cavity and the positions of the main 
outlets. The anterior wall of the cavity was entirely carti-— 
laginous or membranous, and as this portion was not preserved 
in the fossil the opening was stopped with plastic clay which is 
easily detected in the figures; for this reason, the form of the 
olfactory tract and of the pituitary body is not completely shown. 
The olfactory tract was evidently large, as in most of the 
primitive forms, and extended well forward directly beneath 
the upper wall of the skull. The cerebral portion was relatively 
small, scarcely any swelling being revealed in this part of the 
cast except at the posterior end of the prosencephalic region. 
The anterior-lower part of this region was enclosed by the al.-, 
orbitosphenoid bones, and the approximation of the bones of 
the two sides forms notches in two places which indicate the 
points of escape of the nerves which supplied the eye. No 
indication of the origin of the II, III, or IV pair of nerves is 
shown on the cast and no outlets except the notches mentioned. 
It is impossible in the cast to distinguish between the dience- 
phalic and the mesencephalic regions of the brain, but the area 
3 Cope, E. D., Proceedings American Association Advancement of Science, 
Ann Arbor meeting, 1885, and Proceedings American Philosophical Society, 
1886, p. 234. 
Proceedings American Philosophical Society, 1887, p. 219, and American 
Naturalist, vol. 22, 1888, p. 914. 
