DR. J. MURIE ON THE ANATOMY OF THE SEA-LION. 521 
Dimensions in inches. Ratio. 
e. Greatest vertical depth of the fronto-parictal lobe 
(z.é. in a line cutting the postero-parietal gyrus) 2°4 0°68 
* Ditto diameter at the frontal lobes (the point) . . 2°4 — 
** Ditto diameter at the posterior ascending parietal 
IObES! slips 3:1 — 
jf. Length from the front af the middle ioe to higies 
fereeor oye vey 0 0-52 
g- Cerebral radius, occipital . . . .... =. =. 24 0:73 
io, IDL ine 5 GS 6 Gh eae) eee ernie) 0-70 
ta) Ditto; temporo-parictal, 9-06. eh sw fo) 26 0-66 
gj. Ditto, vertical. . ... 2°6 0-56 
k. Projection of the cerebrum ee the ee ee not obtain. 
Cerebellum. 
(Pe the sreatest breadtuie, se ee 8D 1:08 
MamUittomenothe ease een Se Re a® 0°62 
Lee DitiOcdeptie sy arene Lg 1:28 
Measurements of several parts of the brain taken from the preserved specimen, with 
the ratios as in the preceding Table. 
Medulla oblongata. 
gee Greatestipreadthy, 8 es. OBS 0.12 
Corpus callosum. 
Pe venet (ee smite) wk www, 0°48 
WP ANCIAPERINCHCR Es ee sy ew s,s ONT 0°39 
Corpus striatum. 
Roe Leben Ob CHE WISIDIC DALE ee ie wig ve OG 0-72 
EEGs SGI 1S nO 0°80 
Optic thalamus. 
tf. Pewethgot thesyisible partys <2 i<ice) «i «fy iol 0:84 
mea VLCC HEOMCITCOMNE) Valens easdetesccsmbicteaads: jay OF 0°80 
Pons Varolit. 
v. From the upper to the lower border. . . . . . 1°06 1-05 
Uae LC Kn CSS eam emt ae ame alt.) be ape gee O88 0:50 
b. The Cerebral Lobes—Of the five lobes of the cerebrum which most modern 
anatomists recognize in the mammalian brain generally, four are tolerably well defined 
in Otaria—the fifth or central lobe being much less so, if at all distinct. The 
frontal lobes are short, but of moderate breadth and height; their orbital surfaces 
