Zoological Society. 231 



his return to America, together with a preliminary and highly inter- 

 esting sketch of the natural history of the species by its discoverer, 

 who proposes to call it Troglodytes Gorilla, ado])ting the term used 

 by Hanno in describing the wild men which he discovered on the 

 coast of Africa during his famous voyage*. 



Dr. Wyman gives dimensions of the skulls of a male and female 

 Troglodytes Gorilla, with comparative measurements of a character- 

 istic skull of a negro, and those of the Troglodytes niger and Simia 

 satyrus (Sumatran variety, or S. Ahelii) from ray Memoir in Trans. 

 Zool. Soc. vol. i. p. 374 ; and he sums up the following points as 

 showing that from the Troglodytes niger the Trogl. Gorilla '* is readily 

 distinguished — 



"1. By its greater size ; 



*• 2. By the size and form of the supraciliary ridges ; 



"3. By the existence of the large occipital and interparietal crests 

 in the males, and by rudiments of the same in the females ; 



"4. By the great strength and arched form of the zygomatic 

 arches ; 



"5. By the form of the anterior and posterior nasal orifices ; 



"6. By the structure of the infraorbitar canal ; 



"7. By the existence of an emargination on the posterior part of 

 the hard palate ; 



" 8. The incisive alveoli do not project beyond the line of the rest 

 of the face, as in the Chimpanzee and Orang ; 



" 9. The distance between the nasal orifice and the edge of the 

 incisive alveoli is less than in the Chimpanzee ; 



"10. The ossa nasi are more narrow and compressed superiorly." 



The 5th, 7th and 9th are the characters which are most decisively 

 repeated in the Bristol specimens of the skulls of Trogl. Gorilla, and 

 are those that are least ascribable to age or the operation of external 

 circumstances tending to produce a stronger variety of Chimpanzee. 

 The value of the character from size is established by the concurrence 

 of the foregoing more fixed ones. The supraciliary ridges are rela- 

 tively as strongly developed and as prominent in the skull of a female 

 adult Trogl. niger as in that of the Trogl. Gorilla, and they are as 

 angular and rough or uneven in the skull of the adult male Trogl. 

 niger as in that of the adult male Trogl. Gorilla. The male T?'ogl. 

 niger shows also the median prominence between the orbits above 

 the root of the nose. 



In six skulls of Troglodytes niger Dr. Wyman found that " the 

 temporal ridges are generally separated from each other by a space 

 varying from half an inch to one or two inches, according to age, 

 but in none of them is to be seen even a rudiment of the interparietal 

 ridge." In an adult, but by the condition of the teeth, not old 

 male Trogl, niger, the temporal ridges have met above the oblite- 

 rated suture, and developed the rudiment of an ' interparietal ridge,* 

 which would probably have risen above its rudimental state had 

 the exercise of the large temporal muscles been longer continued. 



* See the passage cited at p. 13, ' Falconer's Translation of the Voyage of 

 Hanno,' London, 1797. 



