Robert Bennett Bean. 395 
Fig. 12. Types of the corpus callosum in the Caucasian male. Type I, 
8 subjects; Type II, 7 subjects; Type III, 7 subjects; Type IV, 6 subjects; 
Type V, 4 subjects; composite Type made up of the others, 32 in all. One-half 
natural size. 
Fig. 18. Types of the corpus callosum in the Negro male. Type I, 18 sub- 
jects; Type II, 8 subjects; Type III, 10 subjects; Type IV, 9 subjects; Com- 
posite Type made up of the others, 45 in all. One-half natural size. 
Fic. 14. Types of the corpus callosum in the Caucasian female. Type I, 
1 subject; Type II. 2 subjects; Type III, 1 subject; Type V, 1 subject; Com- 
posite Type made up of the others, 5 in all. One-half natural size. ¥ 
Fig. 15. Types of the corpus callosum in the Negro female. Type I, 5 sub- 
jects; Type II, 3 subjects; Type III, 6 subjects; Type IV, 5 subjects; Com- 
posite Type made up of the others, 19 in all. One-half natural size. 
Fic. 16. Composite types of both races and sexes. Type I, 22 subjects, 
13 Negro and 9 Caucasian. Type II, 29 subjects, 21 Negro and 8 Caucasian. 
Type III, 22 subjects, 15 Negro and 7 Caucasian. Type IV, 28 subjects, 15 
Negro and 13 Caucasian. One-half natural size. 
lines, which signifies that very few Negro brains are found with a brain 
weight of more than 1300 grams, or an area of the genu of more than 
2.60 square centimeters. A majority of the symbols representing Cau- 
casian brains are found above and to the right of the lines, signifying 
that the majority of the Caucasian brains have a brain weight of more 
than 1300 grams, and an area of the genu exceeding 2.60 square centi- 
meters. The converse of these propositions is true. Few Caucasian 
brains have a brain weight of less than 1300 grams or an area of the 
genu less than 2.50 square centimeters, while the majority of the Negro 
brains are in this class. Compare Chart V with Chart VIII and a simi- 
larity is noticed, in fact they are nearly identical, but there is a more de- 
cided identity between the area of the genu and brain weight, than be- 
tween the area of the entire corpus callosum and brain weight. This is 
due to the less decided identity between the area of the splenium and 
brain weight. That the size of the genu and brain weight are closely 
related may be significant in the relation of brain weights in races and in 
distinguished individuals. 
CoMPosITtE 'T'YPES. 
The corpus callosum may be classified in types racially and sexually 
according to the size and shape of the outline of its cross section. One 
hundred and one selected cases are taken and composite outlines are made 
of each racial and sexual type, as, Caucasian male, 5 types; Negro male, 
4 types; Caucasian female, 4 types; and Negro female, 4 types. Com- 
posites are made by selecting outlines similar in size and shape, and 
