250 NAOKI SUGITA 
IV. THE CORTICAL THICKNESS AT SEVERAL LOCALITIES IN THE 
BRAINS OF SOME MAMMALS OTHER THAN THE RAT 
Few papers have been published regarding the differences in 
the thickness of the cerebral cortex at given localities of the brain 
in mammals other than the rat, except for man. Yet even in 
these cases, the techniques of hardening, imbedding, and staining 
used by the different authors are dissimilar and their results are 
accordingly not precisely comparable. Despite this, however, it 
has seemed worth while to make a survey of the data at hand. 
Rabbit. Bevan Lewis (’81) has given as the natural thickness! 
of the cerebral cortex of the adult rabbit the following figures 
(table 3) according to localities. For the localities, the map 
made by him and reproduced by me in a previous paper (Sugita, 
17 a, fig. 10, p. 544) should be here consulted. He has pre- 
sented the thicknesses of every layer of the cortex separately, 
but here only the total cortical thicknesses, as computed by me 
from his data, are given in round numbers. 
Pig. Lewis (’79) has also determined the cortical thickness 
at several localities in the pig brain (the names of the localities 
TABLE 3 
The thickness of the cerebral cortex of the rabbit, quoted from Bevan Lewis (’81) 
Depth of cortex on a plane with genu of corpus callosum: 
mm. 
Gyrus LOGMICAtUS «rect wea o0 6 og te Sk nba ene ye eee tae iz, 
Sagittalvangle: 2.ccrpre +22 ees who ah Sakl Shand sends eet chee ote areola 2.23 
BE ctra-lam biryani oe. & he sis Gane nae oe) eae ee eee ee ee 2.81 
INearilimbiteysmlicnsie heh icy) cauacha ee er ocean eer eee 2.31 
Depth of cortex on a plane with posterior border of corpus callosum: 
Gyrus LOrnVea Lusher rns eo. oe ne ee aoe eee ee ee Rene) eee eee 1.70 
Sapittalianigletss 97 ea. Ua. Me PASO ores Meee es oe eee 1.91 
Txtraslurnioicne 4.4 eae tend cones une: soaked seco ees Ae ae nen a eee 2.46 
Depth of cortex of the modified lower limbic type................. 2.23 to 2.47 
Depth of cortex in the cornu Ammonis: 
Amterlon TEgIONS:. mare tae ian. Soar oe A nr ao ee eee ere PD OA 
Average: atisix differentisites:).|. sehen. a. 3) Loeb aete aotearoa 2a2e 
1 Lewis measured the cortical thickness on sections cut by the freezing micro- 
tome from fresh material and then hardened by osmic acid, stained by aniline 
black and mounted in Canada balsam. According to his statement we obtain, 
by this method, the natural depth of the cortex, no shrinkage occurring if the 
preparations have been carefully made (Lewis, ’78). 
