VII.] BONE, OSSIFICATION, TEETH. 73 



c. The intersystemic lamellae between the 

 Haversian systems ; in the outer part of the 

 bone these run for the most part parallel 

 with the surface. 



d. In the spongy bone the lamellae run in the 

 main concentric to the spaces. 



2. Examine the specimen under a high power. 

 Observe 



a. The irregularly fusiform lacunae giving off 

 numerous wavy branches, the canaliculi, 

 which run across the lamellae to join the 

 similar branches of neighbouring lacunae. 



b. In the compact bone, canaliculi open into the 

 Haversian canal; in the spongy bone into the 

 Haversian spaces and central cavity. 



3. Examine with a low power prepared longitudinal 

 sections of the shaft of a long bone. Observe 



a. The Haversian canals running in the main 

 parallel with the surface of the bone, they 

 have connecting branches and in places open 

 on the surface and into the central cavity. 



b. The lamellae running for the most part 

 parallel with the Haversian canals. Here 

 and there a Haversian system may be cut 

 obliquely, in such cases the lamellae will be 

 concentric to the canal. 



4. Examine the specimen under a high power. 

 The individual lacunae are much as in the trans- 

 verse section, but rather longer; observe the 

 arrangement of the canaliculi (cp. 2). 



