A FISH BRAIN FROM THE COAL MEASURES 155 
to do with its connection to the sacculus. The upper part of 
the left vertical semicircular canals is evident in figures 4 and 15. 
Their connection with the utriculus through the sinus utriculi 
superior is evident in one specimen (fig. 10) in an undisturbed 
relation, which has been used as a basis for this portion in the 
reconstruction (fig. 11). One specimen of a larger brain than 
that shown in figures 15 and 16 shows the horizontal canals in 
position on both sides, with portions of their ampullae. The 
shape of the anterior ampulla (fig. 10, a.a., s.u.a.) is sufficiently 
evident from the drawing. The peculiar enlargement is not 
confined to one specimen, but is determined in all the nodules 
examined, including some from another locality (Baldwin, 
Kansas). 
The sacculus is evident below the semicircular canal but it is 
in such a position that it cannot be shown in lateral view of the 
specimen. Its form is bowl-shaped and it is not possible to 
delimit it from the utriculus, as is shown in the reconstruction 
(fig. 11). The wériculus is well shown in the various figures 
(figs. 10, 11, 15, 16). It joins the vertical semicircular canals 
in an oval sinus utriculi superior. 
VIII. THE DURAL CASTS OF THE BRAIN AND SACRAL 
INTUMESENCE OF THE DINOSAURS 
We owe to Professor Marsh (’74—’96) much of our knowledge 
of the neural anatomy of those gigantic reptiles, the dinosaurs, 
which witnessed the widespread development of this’ class and 
saw the extinction of most of its members. They themselves 
became extinct in the late Cretaceous or early Tertiary at the 
onset of mammals, but before becoming lost to the world they 
attained structural adaptations which will ever be the marvel 
of the paleontological world. 
Since Marsh there have been other workers on dinosaurian 
neurology. Hay (09) has discussed the dural cast of a member 
. of the gigantic horned dinosaurs which is carried further by Lull 
(Hatcher, Marsh, Lull, ’07). Osborn (12) and Brown (14) have 
recently given the best accounts of the anatomy of the dino- 
