RHINENCEPHALON OF DELPHINUS SyAl| 
ing fibers between the two hippocampi is present very distinctly, 
but the anterior commissure is quite minute and it is probable 
that the olfactory portion is entirely lacking. The septum 
pellucidum is very thin. 
Thus, this study of the brain of the dolphin shows that great 
atrophy of the hippocampal formation accompanies loss of the 
external olfactory structures, and that practically all the con- 
necting tracts are likewise suppressed. The fact that both nu- 
cleus amygdalae and ganglion habenulae are present, though 
somewhat reduced, points to their having only a partial con- 
nection with the olfactory mechanism. There is a slight per- 
sistence of the parolfactory cortex, probably sufficient to give 
rise to, at least part of, the fibers of the stria medullaris thalami 
and taenia semicircularis. 
LITERATURE CITED 
Beccart, N. 1910 Illobo paraolfattorio nei Mammiferi. Archivio di Anatomia 
e di Embriologia, vol. 9. 
1911 La sostanza perforata anteriore e i suoi rapporti col rinencefalo 
nel cervello dell’uomo. Archivio di Anatomia e di Embriologia, vol. 
10. 
BINDEWALD, C. 1913 Das Rhinencephalon von Elephas indicus. Zool. Jahrb., 
vol. 35, p. 563-582. 
Broca, P. P. 1878 Le grand lobe limbique, et la scissure limbique dans la 
série des Mammiféres. Revue d’Anthropologie, 2° série, tome 1, p. 
385-498. 
1879 Recherches sur les centres olfactifs. Revue d’ Anthropologie, 
2° série, t. 2, p. 385-455. 
Epincer, L. 1911 Vorlesungen iiber den Bau der Nervésen Zentralorgane. 
Bd. I, Leipzig. 
HatscHEek, R., AND ScHLESINGER, H. 1902 Der Hirnstamm des Delphins. 
Arbeiten aus dem Neurologischen Institute an der Wiener Universi- 
(ui, BCL, @, jos Healt. 
KtKENTHAL, W., AND ZIEHEN, T. 1889 Das Centralnervensystem der Cetaceen. 
Denk. d. med.-nat. Gesell. Jena, Bd. 3. 
Pertit, A. 1905 Description des encéphales. Resultats des Campagnes 
scientifiques de Prince de Monaco, fase. 31. 
Smitn, G. Exxror 1902 Catalogue of the brain collection in the museum of the 
Royal College of Surgeons of England, vol. 2. 
THE JOURNAL OF COMPARATIVE NEUROLOGY, VOL. 25, NO. 5 
