352 



LIEUT. R. BROOM ON THE 



incisors. The premaxillaries are sending up processes which 

 form the bases of the palatine processes. The recurrent cartilages 

 resemble considerably those of the Diprotodont Marsupials, 

 Trichosurus and Pseudochirus. 



In fig. 7, which represents section 114, is seen the anterior 

 part of the maxilla. Here tlie recurrent cartilage is even more 

 Diprotodont- like than in the previous section figured. The 

 section is through the anterior part of the papilla. 



Fig. 8, which represents section 120, is through the naso- 

 palatine canal, It will be observed that the ©anal opens directly 

 up into the nose, as in the typical marsupials. Jacobson's 

 cartilages have given off the outer bars. 



Fig. 9 represents section 123. Here Jacobson's organ is 

 seen opening directly into the lower part of the nasal cavity. 

 This section is strikingly like figures I have given of Jacobson's 

 organ in Pseudochirus and T'v-ichosn.rus. 



In fig. 10, which represents section 126, the organ is seen in 

 its fullest development. 



A short distance behind this last section a small but well 

 chondrified posterior nasal-floor cartilage is developed, The 

 cartilage on passing backwards comes to lie underneath the outer 

 part of Jacobson's cavtilage. 



Figs. 11-13 represent three sections through Jacobson's organ 

 in the young Qhrysocliloris asiatica. Section 11 is through the 

 anterior end of the organ near where it opens into the lower 

 part of the nasal cavity : section 12 is through the middle of the 

 organ, and section 13 near its posterior end. One of the most 

 remarkable characters of the sections is the folding-down of the 

 inferior turhi^al till it almost forms a secondary nasal floor. 

 The organ itself is remarkable in having no outer vascular 

 plexus nor, as is seen in most Marsupials and in Qymnura, Centetes, 

 and Tiijxiia, a lai^ge vessel along the outer side. Further, while 

 the organ in most mammals has a. lai'ge gland or numerous glands 

 opening into it posteriorly, Chrysochlori$ has mucous glands 

 opening into it all along its upper border, 



It will be observed that Ohrysochhris differs in the structure 

 of this region of the nose entirely from Qymnura, Talpa, and 

 Gentetes, and that while it agrees move with Tufaia and 

 MQcro§.ceUdes, the affinity is not close, 



Conclusions. 



The research into the structure of the anterior nasal region of 

 the Insectivores, even though only a few of the more striking 

 types have been examined, shows I think conclusively that 

 the " Iijsectivora " is not a natural order. Erinaceus, Gymnura, 

 Talpa^ Sorex, and Centetes agree in each having an organ of 

 J^cobsqn which ends in a long duct opening i^tq the pasQ-- 



