TUMOURS AND CANCERS. 247 
dular organs, and used this as an explanation of the 
inordinate number of teats found within the pouch of 
some opossums. It is a remarkable fact that one of the 
most typical specimens of cancer that has come under 
my notice in a wild animal occurred in a short-headed 
F1G. 123.—The posterior half of a short-headed Phalanger. ‘The pouch is 
occupied by a cancer, (Nat. size.) 
phalanger (Belideus breviceps) (fig. 123). In this case the 
pouch was occupied by a tumour as big as the kernel 
of a filbert, and when we remember that the parts of the 
phalanger are represented of natural size in the drawing, 
the tumour was relatively large. In order to appreciate 
