164 
MASARU NAGAO 
TABLE I— Concluded 
SKULLS 
ANIMALS 
Types 
Muscuin 
number 
Locality (or race) 
Sex 
Artiodactyla — Continued 
Lama huanacho (guanacho) 
5632 
Zoological Gar- 
den, Philadel- 
phia 
? 
Rangifer tarandus (caribou) 
5487 
Alaska 
9 
5485 
Alaska 
& 
5479 
Alaska 
9 
5477 
Alaska 
9 
5480 
Alaska 
? 
5484 
Alaska 
9 
5475 
Alaska 
9 
Tragulus javanicus (musk deer) 
6045 
Borneo 
? 
6091 
Borneo 
? 
Cervulus muntjac (deer) 
6182 
Borneo 
9 
Sus barbatus (boar) 
2210 
Borneo 
? 
6163 
? 
? 
1569 
Borneo 
cT 
2853 
Borneo 
? 
6150 
? 
? 
Porcus babyrussa (babirusa) 
4773 
Celebes Island 
cf 
Dicotyles sp . (peccary) 
7451 
? 
? 
6202 
? 
? 
6207 
? 
? 
2199 
Brazil 
? 
Marsupialia: 
Didelphys marsupialis (opossum) 
5971 
? 
? 
6005 
? 
? 
6025 
? 
? 
6273 
? 
p 
Spee stated in his paper (1890) that, as the series of teeth in the 
adult human skull lies in a plane not deviating greatly from the sagit- 
tal plane of the skull (the smooth line PQ, — figure 1 — connecting the 
summits of the buccal cusps of the bicuspids and molars having an 
angle 15 to 20 degrees to the sagittal plane, OP, of the skull), it follows 
that the relative position of the teeth does not deviate from their true 
relation if they are projected upon the sagittal plane ^vith a large lens. 
He made photographs of skulls, setting the photographic plates 
parallel to the sagittal plane, and studied the curve on the photographs. 
