284 PROFESSOR OWEN ON THE GORILLA. 
Fig. 1. Upper view, Troglodytes niger. 
Fig. 2. Side view, Troglodytes niger. 
Fig. 3. Upper view, Troglodytes Gorilla. 
Fig. 4. Side view, Troglodytes Gorilla. 
The following symbols apply to each figure :— 
d.i.1. Deciduous mid-incisor, acquired in the human infant at about the 
seventh month. 
d.i.2. Deciduous side-incisor, acquired in the human infant at about the 
eighth to the tenth month. 
d.c. Deciduous canine, acquired in the human infant at about the fourteenth 
to the twentieth month. 
d.m.8. Deciduous anterior molar, answering to the ‘third’ of the typical 
diphyodont dentition, acquired in the human infant at from the 
twelfth to the fourteenth month. 
d.m.4. Deciduous posterior molar, answering to the ‘ fourth’ of the typical 
diphyodont dentition, acquired in the human child at from the 
eighteenth to the thirty-sixth month. 
i. 1 (in figs. 1 & 2). Germ of permanent mid-incisor. 
In regard to the question of the relative degree of approximation to Man, or to the 
position in the animal series, of the Gorilla and Chimpanzee, the above outlines, engraved 
from drawings made with great care in 1860, show the greater absolute size of the 
cranium in the Gorilla; its greater relative size to the face, more especially the greater 
convexity of the frontal bone ; the smaller relative size of the premaxillary (d.i. 1 & 2), 
containing the deciduous incisors; the smaller relative size of those incisors, both to 
the entire skull and to the molars. 
The greater relative size of the deciduous canines in the Gorilla may depend upon a 
difference of sex ; the skull of the young Chimpanzee may have been that of a female: it 
was presented to the Royal College of Surgeons of England, by Earl Spencer, in the year 
1816, and is described in my ‘ Catalogue of the Osteology ’ of that museum, 4to, vol. ii. 
Deol now lil. 
‘ See also the memoir, “ Sur le Gorille,” in the ‘ Bulletin de la Société Linnéenne de Normandie’ (vol. vi. 
Caen, 1861), by the accomplished Professor and Dean of the Faculty of Sciences of Caen, M. Eudes-Deslong- 
champs, in which are given figures of the skulls of the young Orang, Chimpanzee, and Gorilla, and of their 
deciduous dentition, confirmatory of the conclusions to which I had arrived as to their order of precedence in 
the zoological scale. 
