606 



COMPARATIVE PHYSIOLOGY. 



Pie. 445.— TranBvorse section of humerus, 1 x 200 (Sappey). 1, section of vascular 

 (Haversian) cells; 2, longitudinal canal at point of junction with transverse canal. 

 Lacunse and canaliculi arranged in concentric rings. 



tained. A microscopic transverse section shows the substance 

 of the shaft to be penetrated by longitudinal channels (Haver- 



FiG. 446. — Bone-corpuscles and their processes which fill the lacunae and canaliculi 

 (Rollett). 



