THE SKELETON AND ITS JOINTS 371 
growths is well known. The gross diagnosis was sarcoma. 
If this be an original tumor it might be explained as 
arising from ectopic mammary tissue. 
The five other tumors were sarcomata, one of large 
cells almost syncytial in size, shape and number of nuclei, 
two definite spindle cell growths and two of fibrosarcoma 
type. The first occurred in an all-green parrakeet 
{Brotogerys tirica), the second in an undulated grass 
parrakeet {Melopsittacus undulatus) , the third in a larger 
Egyptian gerbille (Gerbillus pyramidum) , the fourth in 
a white-footed mouse {Peromyscus leiccopus), and the 
last in a bean goose {Anser fahalis). 
