362 OLIVER S. STRONG 
artificial deformation when removed. The following observa- 
tions were made upon the external characteristics of the brain, 
most of which were published in a preliminary communication 
(Jour. Comp. Neur., vol. 11, no. 1) and are repeated here, with 
slight changes, for purposes of completeness. 
The most striking feature of the brain, externally, was the 
almost complete absence of the left hemisphere of the cerebellum. 
With the exception noted below, no part of the cerebellum 
extended more than 2 or 2.5 em. to the left of the median line. 
This was true except a small lobe, apparently in part represent- 
ing the flocculus, which protruded some 4 cm. to the left of the 
median line, dorsal to the VIII, IX and X nerves (figs. 1, 2, 3 
and 4). Some preliminary transverse cuts showed apparently 
an absence of the left nucleus dentatus. (Subsequent sections 
revealed a minute left nucleus dentatus.) The inferior and 
superior vermis was apparently in part at least present. It was 
difficult to tell what the left lateral part represented morphologi- 
cally, whether part of the vermis or part of the hemisphere 
(figs. 2,3 and 4). All of the external surface of the cerebellum 
appeared normal, but portions of the left lateral surface revealed 
in sections an irregular, disordered histological arrangement 
(p. 369). 
The cause of the agenesia was not clear, it was possibly due to 
some old, prenatal, cyst which occupied the space which should 
have been filled by the left cerebellar hemisphere. 
On the ventral aspect (figs. 1 and 2), the right olivary body was 
apparently entirely absent (cuts made through the medulla have 
shown that a moiety of it was present) ; the left olivary body was 
normal. The cranial nerves were apparently normal. 
The pons was highly asymmetrical. The transverse fibers, 
as viewed externally, were normal on the right side but enorm- 
ously reduced on the left side laterally to the protuberance of the 
pons caused by the longitudinal tracts and nuclei within (i.e. 
the left middle cerebellar peduncle), so much reduced that the 
V and VII nerves, instead of being separated by the usual mass 
of transverse pontile fibers, issued from the pons in immediate 
contiguity to each other. On the other hand, the pons pro- 
