872 DR. a. F. SONNTAG ON THE VISCERAL ANATOMY 



aperture has the form of the figure 8, and the rima glottidis is 

 invisible. In jEpyprymnits r^ifescens, Macropus hennetti, and 

 Macropus giganteus the apex of the prominent epiglottis has a 

 small sharply-cut notch resembling that in Trichosurus vulp)ecula, 

 and much emargination is present. The notches in the Polyproto- 

 dont, on the other hand, are wider and shallower. 



Owen (10) states that the epiglottis of the Phalangers is broad 

 and bifid, but I found it entire and slightly concave in a mam- 

 mary foetus of Phalanger orientcdis. It is entire in Pseudochirus 

 peregrinus, Petaurus sciureus, Petaurus hreviceps, and Petcmrus 

 hreviceps var. papuanus. In Petaurus sciureus the degree of 

 emargination is considerable. 



The large entire epiglottides in Phasolarctos cinereus (15) and 

 Coenolestes obscurus (9) have already been described. 



The characters of the other cartilages, and the cords, ventricles, 

 and muscles are described by Owen. 



The trachea is usually long and narrow, but it is short and wide 

 in Phascolarctos cinereus. The cartilages frequently form com- 

 plete rings, but in many species they are defective behind and a 

 membrane fills the gap. Some of the rings are expanded and 

 thickened on one side, and the numbers observed were : — Meta- 

 chirus opossum 19 ; Perameles ohesula 34 ; Petaurus sciitreus 35 ; 

 Dendrolagus torsinus 35. The numbers in other Marsupials have 

 been recorded by Cunningham (3), Osgood (9), and Owen (10). 

 In Marsupials in which the vagus and sympathetic are separate, 

 the tracheal and pulmonary plexuses are large. 



The Lungs : — My observations difi'er from those of Owen (10) 

 in a number of cases. In the Didelphyidfe the right lung is 

 trilobate and has a well-marked azygos lobe. The left lung is 

 entire in Metachirus opossum, but is bilobate in Marmosa elegans. 

 In Perameles ohesula the right lung has three lobes and an azygos 

 appendage, and the left one is entire : Owen also states that the 

 left lung of Perameles is undivided. The Phalangeridse have 

 bilobate left lungs, and the right ones are trilobate with the 

 azygos lobe in addition. In the Macropodidsp, of which Dendro- 

 lagus ii^r sinus, Alacropus hennetti, and Macropus giganteAis were 

 examined, both lungs have deep median sulci dividing them into 

 anterior and posterior parts, but these are not entirely separated 

 from one another, and the azygos lobe is large. The conditions 

 difiTer from those of other Kangaroos described by Owen (10). 

 The mesial borders of the lungs are thin in the Macropodidse. 



The division of the lungs appears to difiTer considerably even in 

 the same species. Osgood (9) observed variations in Coenolestes 

 obscurus, and Owen, Forbes, and I have recorded three dififerent 

 arrangements in Phascolat'ctos ciiiereus. I am unawai-e of any 

 account of the lobes of the lungs of the uterine foetus, and it is 

 important to ascertain whether there is fusion of lobes of the left 

 lung during development similar to that which takes place in 

 Bradypus tridactylus, in which the foetal lungs are divided into 

 lobes : but those of the adult are entire. 



