BY R. BROOM. 599 



The organ itself in the region of best development (fig. 9) has 

 on section the visual kidney shape. There is some resemblance to 

 the organ in Dasyurus, with which it agrees in having a single 

 vessel along the hilus; in Didelphys, however, the blood vessel is 

 considei"ably smaller. The sensory region is well developed, the 

 upper and lower ends of which curve towards each other constrict- 

 ing the hilar region slightly. In the hilar region ai'e a few 

 mucous glands which open into the organ at the point of union 

 of the upper end of the sensory wall with the non-sensory. The 

 main nerves lie as usual in the little triangular space above the 

 organ. 



PERAMELID^. (Plate xliii.) 



In the Bandicoots I have confined myself to the study of one 

 species, Perameles nasuta; of which I have examined — (1) a young 

 mammary ftetus; (2) a half grown specimen; and (3) an adult. 

 To Mr. A. G. Hamilton, of Mt. Kembla, N.S.W., I am indebted 

 for the fcetus and the adult specimen. 



Perameles nasuta, E. Geoff., (mammary foetus, head length 

 21 mm.). In a section through the developing first upper incisor, 

 and also a little in front of and behind this plane, the nasal-floor 

 cartilage will be found to be well developed and moderately flat. 

 By each side of the base of the septum is a rather large inferior 

 septal ridge, and into the base of it, at least, passes an ascending 

 plate of the nasal-floor cartilage, lying close to the septum. This 

 ascending plate is better developed anteriorly in this genus than 

 in either Dasjairus or Didelphys. On reaching the papillary 

 planes the septum is found to have retreated, and its place to have 

 become occupied between the two ascending plates of the nasal- 

 floor cartilage by the two palatine processes of the premaxillary 

 (fig. 1). This very marked retreating of the base of the septum 

 is greater than in the other Marsupials, and recalls the condition 

 in the Insectivora. In fig. 1 is shown the moderately developed 

 papillary cartilage, by the edge of which the naso-palatine canal 

 is seen entering. Here also the well developed nasal-floor cartilage 

 is seen passing up and curving round into the sej^tal ridge forming 



