XIII. J THE FROG. 245 



e. Besides the lamellae above mentioned others 

 will be seen which belong to no Haversiari 

 system, but either fit in the angles between the 

 systems, or run around the outer surface of the 

 bone. 



b. Examine with J obj. Observe the lacunas and 

 canaliculi more accurately. 



c. Examine in water or glycerine a thin transverse 

 section of a long bone which has been softened by 

 dilute acid. 



a . The Haversian canals empty or containing a 

 granular mass. 



/3. The lamellce : very indistinct. 



<y. The lacunce seen as transparent oval spaces. 



8. The canaliculi transparent and almost invisible. 



d. Examine sections of softened bone which have 

 been stained with carmine : in each lacuna will be 

 found a stained mass of protoplasm. 



e. Examine longitudinal sections of the femur or 

 humerus : the Haversian canals are seen to be 

 channels running for the most part in the long 

 axis of the bone, but communicating with one 

 another frequently by cross branches. The 

 lacunae, &c. appear much as in the transverse 

 section. 



d. Connective tissue. 



1. Of this there are two main varieties, viz. 



a. White fibrous tissue. This occurs nearly pure in 

 tendons, but is widely distributed throughout the 



