32 



DISSECTION OF THE DOG 



incisions have just been made through that portion of the parietal pleura 

 which is applied to the ribs and therefore called the costal pleura (pleura 



m. rhomboideus thoracalis 

 m. serratns ventralis , 



m. subscapularis / / 



m. serratus dorsalis 



m. longissimus dorsi 



?n. Uio-costalis 

 Costa 3 



m. iongus colli 

 (Esophagus 

 Trachea 



Vena cava cranialis 



Humerus 



Sternum 



Thymus 

 Fig. 9. — Transverse section of the thorax on a level with the third thoracic vertebra. 



