556 MR. JAMES JOHNSTONE ON THE 



EXPLANATION OF THE PLATES. 



Plate 37. 



Fig. 1. Thoracic organs oi Basyiirus viverrinus. J nat. size. 



2. Dissection of thorax and lower neck of a young Trichosurus vulpecula. 



1|- nat. size. 



3. Dissection of the neck of Perameles Gunni. | nat. size. 



4. Dissection from the ventral side of the thorax and lower part of the 



neck of Tki/lacinus. About |- nat. size. 



5. Dissection of thorax of Cuscus orientalis. Nat. size. 



Plate 38. 



Eig. 6. Longitudinal section of part of the thorax of Macropus Eugenii a little 

 to the left of the middle line of the body. Mag. about 30 diameters. 



7. Longitudinal section through the neck of Macropus Eugenii, to the 



left of the middle line. Mag. about 30 diameters. 



8. Macropus Wilcoxii. Transverse section of thorax. Mag. about 40 dia- 



meters. 



9. Perameles Gunni. Transverse section of thorax a little below the 1st 



rib. Mag. about 13 diameters. 



Plate 39. 



Fig. 10. Transverse section of the thoracic organs of Bidelphys pusilla. Mag. 

 10 diameters. 



11. Macropus Wilcoxii. Transverse section of part of the posterior lobe of 



the thoracic thymus. Mag. about 200 diameters. 



12. Macrojms Wilcoxii. Transverse section of the anterior lobe of the 



thoracic thymus. Mag. about 200 diameters. 



13. Macropus Wilcoxii. Transverse section of part of the thorax, passing 



through the anterior lobes of the thoracic thymus. Mag. about 

 30 diameters. 



Eefereiice Letters. 



a.c'. Eight common carotid artery, 

 a.c". Left common carotid artery. 

 a.sc'. Blight subclavian artery. 

 a.sc". Left subclavian artery. 

 a.i. Innominate artery. 

 an. Solid anastomosis between the superior venae cavte. 



b. Placed in the bay formed by the flexure of the head. 



c. Centrum, of vertebra. 



c.c. Cellular tract uniting cervical thymus and lateral lobe of thyroid. 



cr. Cricoid cartilage of the larynx. 



d. Clavicle. 

 dp. Diaphragm. 

 f. Fat. 



