24 Dr. Kneeland on the Skeleton of the Great Chimpanzee. 



orbitar angles of the frontals seems to confirm Dr. Wyman's * 

 opinion that it is an independent piece, having its own centre of 

 ossification ; the foramen existing midway between the incisive 

 foramen of each side and the edge of the alveolus, on the left 

 side is replaced by two as in the Chimpanzee. The zygomatic 

 arches are exceedingly strong, enclosing temporal muscles of 

 immense size. The other anatomical peculiarities of the cranium 

 and face have been sufficiently detailed by Dr. Wyman {op. cit.). 

 The following points are interesting : — the dental formula is the 

 same as in Man ; the median upper incisors are twice the size of 

 the lateral, the reverse of which is the case in the lower jaw; 

 they are also respectively longer, giving to the upper incisors a 

 convex edge, and to the lower a concave one : in the upper jaw 

 there is an interval of two or three lines between the incisors and 

 canines, and no interval between the latter and the premolars, 

 the reverse being the case in the lower jaw, in which, however, 

 the interval is less : the upper canines extend from the alveolus 

 \~ inch, the part within the alveolus being at least 2 inches; 

 they are an inch broad and | of an inch thick ; the upper canines 

 are worn anteriorly by the lower, and posteriorly by the first 

 lower premolar, giving to the tooth a triangular shape, with an 

 anterior, a posterior, and an internal cutting edge ; the action of 

 the lower premolar on the upper canine, and of the latter on the 

 lower canine, produces a distinct talon, or heel, at the base of these 

 teeth : the two grooves mentioned by Dr. Wyman as occurring 

 on the inner face are not seen in these canines, probably from 

 the extent of the worn surface ; there is the lower portion of a 

 single groove, however, which is lost in the worn surface beyond : 

 to produce these surfaces there must be some lateral motion of 

 the jaw, which would hardly be expected from the great length 

 of these teeth. The premolars and molars agree with Owen's 

 description in the ' Cyclopsedia of Anatomy and Physiology ' 

 (Art. Teeth) ; the first lower premolar is much larger than the 

 second, the anterior cusp being so strongly developed, and the 

 posterior so little, that the tooth resembles an enlarged human 

 canine ; all the lower molars have three cusps on the outside and 

 two on the inside. The lower jaw is of great strength, the ramus 

 being at right angles with the body of the bone ; the condyle is 

 1| inch wide and | of an inch thick, projecting much internally : 

 the coronoid process is higher than the condyle. The external 

 face of the ramus is deeply concave for the masseter muscle, 

 which is nearly 3 inches wide ; the ramus inclines very much 

 outwardly at its lower portion, and is grooved internally for the 

 mternal pterygoid muscle : the body of the jaw is If inch high, 



* Boston Journal of Natural History, vol. v. p. 42fi. 



