THYMUS IN THE MARSUPIALS. 



ff.s. Sympathetic ganglioa. 

 is. Isthmus of thyroid. 

 I. Lung. 

 m.sh. Sternohyoid muscle. 

 m.oh. Omohyoid aiuscle. 

 m.sm. Sternomastoid muscle. 

 m.p. Pectoralis muscle. 

 m.st. Sternothyroid muscle. 

 oe. Esophagus. 

 pc. Pericardium. 

 st. Sternum. 

 sm. Submaxillary gland. 

 tm. Thymus. 

 tm.a. Anterior lobe of thoracic thymus. 

 tm.c. Cervical lobe of thymus. 

 tm.p. Posterior lobe of thoracic thymus. 

 th. Median lobe of thyroid. 

 th'. Right lobe of thyroid. 

 th". Left lobe of thyroid 



tr. Trachea. 

 v.e'. Right superior cava. 

 v.c" . Left superior cava. 

 vg. Vagus nerve. 

 v.j'. Internal jugular vein. 

 v.j". External jugular vein. 

 /., //., ///. Ribs 1 to 3. 



557 



LIKN. JOUBN. — ZOOLOGY, VOL. XXVI. 



