158 THE VOYAGE OF H.M.S CHALLENGER. 



Mr. Martin states that " six coronary veins entered the right auricle round its junctional 

 margin with the ventricle." ' These were undoubtedly the small cardiac veins which 

 ascend upon the anterior wall of the right ventricle. 



Mr. Marshall 2 in his memoir upon the development of the great anterior veins 

 divides mammals into groups, according to the manner in which these veins are arranged. 

 In the first group, which consists of those animals in which the right and left anterior 

 venae cavae persist, and in which the great coronary and other veins in its course join the 

 left anterior vena cava, he places the Marsupials. If, however, the arrangement of the 

 coronary veins, which was so evident in the Thylacine is general through Marsupialia, they 

 cannot be included in this group ; indeed, they represent a mode of termination of the 

 great cardiac vein, which, so far as I am aware, has not been noticed in any other mammal. 



Trachea and Lungs. 

 Trachea. — The following is the length of the trachea as it was exhibited in each 



o o 



marsupial examined : — 



Thylacine, . . 6| inches, . . 34 cartilaginous rings. 



. . 26 



25 

 29 



» ■ • " ;> 



21 



In the Thylacine, Cusctis, Dasyure, and Phascogale the tracheal rings were deficient 

 superiorly throughout the entire length of the tube ; in the Vulpine phalanger they 

 constituted complete rings round the tube in the anterior half of the windpipe ; behind 

 this they were deficient above. 



Lungs. — In the Thylacine and Dasyure the left lung is undivided by any marked 

 fissure, in the former, however, the margin is deeply crenated, whereas in the latter it is 

 uniform. In the Cuscus, Phascogale, and Vulpine phalanger the left lung is partially 

 divided into two lobes of nearly equal bulk by a fissure which extends upwards from 

 the lower sharp mai'gin. 



In each case the right lung is furnished with a well-marked pyramidal azygos lobe 

 which is separated from the right lung by the posterior vena cava, and rests by its 

 base upon the upper surface of the diaphragm. 



In all the animals examined the right lung is divided into three lobes. This sub- 

 division, however, is not nearly so well marked in the Thylacine as in the others. 



Abdominal Viscera. 



Thylacine. 

 Stomach. — The distended stomach of the Thylacine has a close resemblance to that 



1 Proc. Zool. Soc, 1836. ■ Phil. Trans., vol. cl., 1850, p. 150. 



