16 ELEMENTS OF MAMMALIAN ANATOMY. 
material known as feces passed out of the alimentary canal 
through the anus is not an excretion of the cells of the body, 
but largely that portion of the food not transformed into a 
condition permitting it to be absorbed by the villi. 
Fic. 11. Fisers oF CoNNECTIVE Tissue. X 300. 
In addition to these systems necessary for the mainten- 
ance of life, the cat requires a means for supporting the 
body and moving about, furnished by the osseous and 
muscular systems. The osseous system serves not only for 
support and locomotion, but also for the protection of the 
delicate vital organs. The skull and spinal column contain 
the brain and spinal cord, while the heart and lungs are 
well shielded by the dorsal vertebre, the ribs, and sternum. 
Likewise the muscles ward off serious injuries from the 
blood-vessels, as they cover to a considerable depth nearly 
