PHYSIOLOGY, AND PATHOLOGY OP THE CHIMPANZEE. 339 



the occiput to the seventh dorsal spine. The sheet is undivided 

 into major and minor muscles, in which it agrees with that 

 described by Gratiolet (22), A^rolik (51), Macalister (33), Bland- 

 Sutton (4), and Wilder (53). Champneys (22) describes major 

 and minor rhomboids in great detail. 



The levator anguli scapulae (text-fig, 33, L.A.S) arises by five 

 slips from the posterior tubercles of the first five cervical vertebrae, 

 the first being the largest. The lower three origins are tendinous 

 and fused with splenius cervicis. It is inserted into the upper 

 fourth of the vertebral border of the scapula. It is not adherent 

 to serratus magnus, nor is it divisible into two parts. Champ- 

 neys (11) gives the origin as the first two cervical vertebrae ; 

 Gratiolet (22) gives it as the second and third ; Hepburn (24) 

 records origins from three cervical vertebrae ; Wilder (53) gives it 

 as in Man, and Bland-Sutton (4) records it as springing from the 

 first five. 



The ser7'atus posticus superior (text-fig. 33, S.P.S) arises by a 

 thin aponeurosis from the spinous processes of the seventh 

 cervical and first dorsal vertebrae, and it is inserted by four 

 muscular slips into the outer surfaces of the first four ribs at 

 their angles. Macalister (33) describes it crossing the first two 

 ribs to be attached to the third and fourth. The serratus posticus 

 inferior arises from the posterior lamella of the lumbo-dorsal 

 fascia and sweeps antero-laterally to be inserted into the lower 

 borders of ribs nine to thirteen just external to their angles. 

 Bland-Sutton (4) gives its attachments as ribs nine to twelve. 



The lumho-dorsal fascia is arranged as in Man. The thoracic 

 part is thin and transparent, and it is difiicult to separate it ofi' 

 from the subjacent muscles as a continuous sheet. The lumbar 

 part is very dense and strong. The posterior lamella is not easily 

 separated from the latissimus dorsi, to which it gives origin. 

 Posterior branches of the spinal nerves pass through its deep 

 surface. In its lower part it gives origin to the serratus posticus 

 inferior. Between the outer and middle lamellae the erector 

 spinae is present, and the attachments of the middle lamella are as 

 in Man. The quadratus lumborum lies between the moderately 

 strong middle lamella and the weaker internal lamella, whose 

 attachments to the arcuate ligaments of the diaphragm are as 

 in Man. 



In the possession of a serratus posticus inferior the Chimpanzee 

 resembles Man, and that muscle is one of the three charac- 

 teristically human muscles. It will be seen later that the 

 Chimpanzee possesses the plantaris, which is the second human 

 muscle, but it does not possess the peroneus tertius. 



The muscles of the back described above are relatively stronger 

 than in Man, and they are relatively weaker than the pectorales, 

 but the total bulk of these groups has probably diminished 

 during captivity. 



The splenius (text-fig. 33) arises from the sides of the tips of 

 the fifth, sixth, and seventh cervical vertebrae, and fi'om the spines 



