632 REPORT OF THE HARVARD AFRICAN EXPEDITION 
After taking all things into consideration my conclusion is that the gorilla, 
particularly the adult male, shows a large individual variation even within the 
limits of a small area; that there is no difference in kind between the Coast and 
the Mountain gorillas such as to justify making of them two separate species, 
but that there is a distinct difference in degree sufficiently important to constitute 
a subspecific difference between the two groups. While I have reached fairly 
definite conclusions based on a careful study of all available material, I fully 
realize that other conclusions may be reached by future investigators when 
further masses of material have been accumulated. 
Revised Classification: 
Genus and Species: Gorilla gorilla 
Gorilla gorilla gorilla (Savage and Wyman) or Coast 
Gorilla gorilla beringet Matschie — Mountain 
The external characters that distinguish the Mountain from the Coast 
gorilla are, besides a longer palate and a generally narrower skull, the thicker 
pelage, shorter arms and longer legs, large amount of black hair, and fleshy 
callosity on the crest. 
A table of average skull measurements is here appended for the Coast sub- 
species and the Mountain subspecies. 
Average Skull Measurements of Coast and Mountain Gorillas 
(Based on Study of 310 Adult Male Skulls) 
COAST MOUNTAIN 
mm. mm. 
Le) Greatest lenothin ry... dates. ote ucunc be eee 296 292 
Bao HAS CONT AUGY WUC: 9, acl gees 2 2 « «> Re ee 179 174.1 
cpa Meme LEMOGI « etx aay, <2 5. osteo sole eRe ee eee 193 188 
As! CATaEL WACLGMe. Ge Oise t eer aces oe eaaes & 4s a. occa eee ea 103.8 98.3 
De Oneal Wren paciwx, te) sos Slvdas face cones 114 113.5 
Ge sOnbntal wads sa. scr yh a skh ix.< . Su. 5 he Ee 114 108 
tie MEASURE. WP LGL Ulli. Sp cavet, Xe G Weevage boos Da, ee ee 159 154.9 
DP ELCIS Ob/OL OCA: s.4.0c.a8 ehs.a eos vas a+ > oe eee 97 96.6 
Dyemis sb lsh sLOni Oly anise ee< oe dow crete 6d < 14 ae ee Ws} 125.8 
LOR SCM cau te a ee 196 204 
Is) CR MAGEN OTN BOMaSIOM, 2s oto gece s 1s «2+ he An eee 124.8 126.3 
hae IN MSIOtie Or DABION, un ee oy oe. # fs >. in Doe 136.8 134.8 
13. Outside mtercondylar width......................... 145 142.5 
14, Outside intercoronoid width......................... 125.4 114 
Mu OIiCy RI WACIC Hot eo: am bir ode inde au os « oon soe eave ¢ OR 37.2 35.7 
16. Length of ascending process of ramus................. 73.8 75.6 
17. Height of ascending process of ramus................. 120 123.5 
18. Greatest width across jaws posteriorly................ 124.8 136.8 
19, Length of maxillary rOW...22.0......+<..seescens, cee, 87.8 92 
20. Outside alveolar width, upper tooth row............... 13 TAL. 
21. Inside alveolar width, upper tooth row................ 40.6 37.3 
22. Length of mandibular tooth row...................... 96.3 101 
23. Mandibular width outside alveoli..................... 65.2 68.5 
24, Mandibular width inside alveoli...................... Pa) 36.8 
25. Orbital arc using a base of 50 millimeters............_. 74 69.7 
26. Sagittal arc using a base of 50 millimeters..........._. 97 92.5 
