SpitzKA, Brain-Weights of Animals. 17 
Ratios of Body-weights and Brain-weights. 
(Brain-weight—1.) 
Total of 8 cases, Fo7540. 20; 
5 Males (4590-8610) ey Mee 
3 Females (2287-3580) erie fe 
Other Spectes of Macacus. Five specimens of M. sznicus, 
the same number of J. pileatus are all too young to furnish 
reliable ratios. The average brain-weight of MW. sénzcus (maxi- 
mum 75 gms.) is 67.6 gms. Of M. pileatus (maximum 72 
gms.) is 63.1 gms. 
An adult specimen of WM. sfeciosus (3) weighing 5560 
gms. has a brain-weight of 98 gms., giving a brain ratio of 
1:57. The brain of a young specimen (?) weighs 81 gms. 
A single specimen of J. melanotus has a brain-weight of 80 
gms. 
Judging from these records and allowing for disturbing 
factors, the following tabulation of the absolute and relative 
brain-weights, with their variations, may be here proposed. 
The sexual differences are not discussed at present, for the 
number of adult specimens is far too small for accurate analysis. 
Asa rule, however, the females seem to have a smaller brain- 
weight, both absolutely and relatively, although the reverse 
would appear to be true were the total of the tabulated cases to 
be alone considered. 
The list of ‘‘ Probable Averages” in Table V is only 
tentatively proposed, for the accession of a larger number of 
adult specimens may materially change certain of the figures. 
Bie Bei. 
PROBABLE AVERAGES OF BRAIN-WEIGHTS IN THE GENUS MACACUS. 
Probable Ay- 
erage Brain- 
Probable Av- 
Usual Range of erage Adult 
Brain-weight. weight. Ratio. 
Macacus rhesus, 70— 90 gms. 80 gms. Tc5s 
“«« cynomolgus, 50- 70 *§ Gouss I: 50? 
Ks nemestrinus, 95-120 ‘ LILO ee 170 
to sinieus; 65-75 <* 70; <é ? 
J pileatuss 60- 70 ‘< 65s I: 50? 
‘« _speciosus, 80-100 ‘ gone. I: 60 
