A FISH BRAIN FROM THE COAL MEASURES 157 
tumesence as in other animals. Streeter?®> working on the os- 
trich, has described and figured the ‘lumbar brain’ in detail and 
comparatively with the brain and spinal cord. The spinal cord 
in this large bird does not fill the dural cavity of the vertebrae, 
nor does the lumbo-sacral intumesence have more than half the 
diameter of the brain. It is probable that in the dinosaurs the 
dura mater was the periosteum of the spinal canal. It is also 
probable, as in the ostrich, that there was a large space between 
the walls of the canal and the cord filled with arachnoid. There 
is, however, this difference: the head of the ostrich is propor- 
tionately larger than in the dinosaurs (Diplodocus) under con- 
sideration. In birds the brain more nearly fills the brain case 
than in the reptiles, and it has a larger development. While it 
may not be precisely true that the ‘lumbar brain’ in the saur- 
opodous dinosaurs was ten-times the size of the cephalic brain, yet 
every feature in their anatomy points to tbe conclusion that it 
was several times larger; a truly anomalous condition where the 
greatest mass of nervous tissue is located in the sacral region 
(figs? 1:2), | 
Brown (714) has recently published some most interesting fig- 
ures of brain casts and apparently complete inner ears of a new 
type of dinosaur. While it is to be regretted that Brown has 
not given us a more detailed study of these sensory structures, 
yet it is interesting to note the enormous possibilities offered by 
fossil material for the elucidation of anatomical features. When 
paleontologists have worked over all of the taxonomic possi- 
bilities of fossil vertebrates it is to be hoped that some will turn 
their attention to the description of anatomical structures as 
they occur in these fossil vertebrates. 
IX. THE BRAIN AND EAR OF A PTERODACTYL 
Newton (’88) has given a careful account of the brain cast of 
a flying reptile, Secaphognathus, one of the Liassic pterodactyls. 
This cast is apparently a much more accurate copy of the brain 
than is the case in brain casts of other reptiles, the dinosaurs for 
instance. It has been thought worth while in this review to 
*> Streeter. Amer. Jour. Anat., vol. 3, no. 1, pp. 1-27, figs. 2-6. 
