41 
of cords and cells. In such places the nuclei are 
hyperchromatic and gradually fuse with the ab- 
normal tissue. The latter consists of closely- 
packed round or polygonal cells with hyperchro- 
matic nuclei. For the most part the cells are 
placed diffusely, but in a few places a disorderly 
attempt at cord formation can be made out. 
2665. Blood-breasted Pigeon {Phlogoenas luzonica): 
Multiple osteomata of bones and lower beak. 
Both sides of the lower beak are bulged out into a 
fusiform hard swelling. Such swelling is not ulcer- 
ated, but is covered by the black, dark, muco- 
cutaneous epithelium. Upon skinning the bird, 
other swellings are found — several nodules at the 
tips of each wing, a single nodule at junction of 
third rib and spine on each side, a long irregular 
bunch in pelvis near kidneys — again bilateral. 
They are all of a creamy yellow color, roughly 
nodular, firm like leather, with a gritty suggestion 
upon incising. They do not bleed. No other 
lesions could be found in the bird. 
The microscopical section has the usual character- 
istics of bone except that much of the trabecular 
substance is not calcified. Bone formation does 
not seem to be going on very rapidly. The mar- 
row spaces, as expected, are large, with broad air 
spaces, while the trabeculse are narrow. 
2668. Common Opossum (Didelphys virginiana) : 
Fibro-osteoma of jaw. 
Both sides of the upper jaw are involved by a dense, 
rounded tumor. It projects from the external 
surface of the gum. It is pinkish-white, not ul- 
cerated, but covered by smooth glistening mucosa. 
It is the size of a pigeon's egg. It cuts like leather, 
with an occasional gritty suggestion. It does not 
bleed on section. 
