200 THE GENERAL ANATOMY OF GORILLA [SECT. A 



In the sympathetic chain three cervical ganglia are found, in addition 

 to the ganglion stellatum; the second and third ganglia are placed more 

 anteriorly than in Man. The sympathetic chain, the splanchnic nerves, and 

 the vena hemiazygos pass together through the diaphragm. A ganglion 

 meseraicum medium, not found in Man, lies between the aortic and coeliac 

 plexuses. In many instances a single sympathetic ganglion is connected with 

 two or more spinal nerves, and vice versd a single spinal nerve may send 

 contributory fibres to two sympathetic ganglia. 



The general distribution of cutaneous nerves to the lower limb 

 of a Chimpanzee is shewn in the accompanying illustrations. 

 (Figs. 129, 130, 131.) 



I. Respiratory System. In an adult male Gorilla (specimen 

 " Cy," Mus. Anat. Cant.) the hyoid bone is provided with a larger 

 cornu majus than in Man. The basi-hyoid is excavated inferiorly, 

 the cavity being sufficiently large to admit the tip of the little 

 finger. (It is occupied by a diverticulum of the conjoined sacculi 

 to be described presently.) The thyroid cartilage is rather smaller 

 than its human representative, and thus stands in marked contrast 

 to that of the Orang-utan. (The cricoid cartilage on the other 

 hand is larger than in Man.) The superior thyroid cornu nearly 

 touches the greater cornu of the hyoid bone. 



The laryngeal pouches (cf. Fig. 121, supra) are of enormous 

 extent. An appendix emerges over the superior border of the 

 thyroid cartilage. After providing a large diverticulum towards 

 the basis cranii, it becomes confluent with the saccule of the 

 opposite side and from this junction, an " infra-hyoid " diverticulum 

 proceeds upwards to excavate the hyoid bone (Fig. 132). 



The conjoined saccules cover the larynx superficially and large 

 symmetrical diverticula pass beneath the clavicles and pectoral 

 muscles. An inter-pectoral diverticulum having been given off, 

 the saccules are finally traceable to the axillae. In females and in 

 immature examples, the extent of these pouches falls considerably 

 short of this, the arrangement in an adult male. As regards the 

 function of these parts, we may accept provisionally the suggestion 

 of Deniker, that the pouches serve the purpose not only of resonators 

 for vocal efforts, but of supporting the lower jaw and parts of the 

 head, and consequently of relieving the pressure of these weighty 

 structures on the trachea. 



