BY R. BROOM. 609 



In the lower part of the section the naso-palatine canal is seen 

 cut across. 



On reaching the plane where the prem axillary' gi\es off its 

 palatine process the nasal-floor cartilage is found to bend down 

 into the gap formed, as seen on the left side of PI. XLVI. fig. 8. 

 There is no more than a slight indication of a downward process 

 apart from the general dijjping down and thickening of the nasal- 

 floor cartilage. The palatine process is by the side of the lower 

 third of the downward bent cartilage; while the naso-palatine 

 canal is seen almost in contact with the lower part of the cartilage. 

 On the right side of the same figure is seen the condition a little 

 farther back. The large solid downward extension has given way 

 before the ascending naso-palatine canal, and there is formed a 

 well marked inner plate, extending from the side of the base of 

 the septum, down past the vomer and along the upper half of the 

 palatine process. From the upper end of this plate there passes 

 an outward and downward process which becomes continuous with 

 the outer part of the nasal-floor cartilage. In PL XLVi. fig. 9 we 

 see the inner part of the nasal-floor cartilage or Jacobson's cartilage 

 separated from the outer. It has a well developed inner concave 

 plate, with above a downward and outward sloping roof. In the 

 hollow is the anterior part of Jacobson's organ connected with 

 the nasopalatine canal near the point where it merges into the 

 nasal cavity. 



Beyond this plane thei-e is found passing up from the lower 

 edge of the inner plate a process meeting the lower edge of the 

 roof and forming a complete cartilaginous tube for the organ. 



The organ itself, however, is very feebly developed relatively, 

 though it possesses the usual sensory wall. There are very few 

 glands in the tube; but it is extremel}^ interesting to find a plexus 

 of five or six large veins on the outer side of the organ. The 

 whole length of the organ is somewhat less than 10 mm. 



MACROPODIDtE. (Plate XLVir.) 



Of the Kangaroo group, Symington, as alread}' stated, has 

 examined the small mammary ftvtus of Macropus gigauteus and 



