NO. 3 



COMPARATIVE HISTOLOGY OF FEMUR POOTE 



191 



The internal circumferential lamella? form a narrow ring around the medulla^ 

 canal. 



Type III, C, senile. 



RIGHT FEMUR OF A WHITE MALE. NO. 167, MED. DEPT. NORTHWESTERN UNIV. 



Pl. 30, Fig. 392. Syn. Tab. X 



Antero-posterior diameter of bone, 27 mm. ; lateral, 25 mm. 

 Antero-posterior diameter of medullary canal, 14 mm. ; lateral, 11 mm. 

 The medullary canal is full. Medullary index, 30%. 



Structure. — The external circumferential lamella? are fragmentary. For 

 the most part, Haversian systems form the external boundary of the section. 

 The central ring is composed of Haversian systems and inter-Haversian lamellae 

 in the inner wall and of Haversian systems elsewhere. The internal circum- 

 ferential lamella? are fragmentary. 



Type III, C, senile. 



RIGHT FEMUR OF A WHITE MALE. NO. 172, MED. DEPT. NORTHWESTERN UNIV. 



Pl. 30, Fig. 393. Syn. Tab. X 



Antero-posterior diameter of bone, 32 mm. ; lateral, 31.5 mm. 

 Antero-posterior diameter of medullary canal, 17.5 mm. ; lateral, 18 mm. 

 The medullary canal is full. Medullary index, 45%. 



Structure. — A narrow band of external circumferential lamella?, somewhat 

 fragmentary, forms the external boundary of the section. The central ring is 

 composed of Haversian systems, well developed and of varying sizes. In the 

 anterior and inner wall, the systems are separated by a little inter-Haversian 

 structure. Many senile systems appear. Few cross canals are seen. The 

 internal circumferential lamella? are fragmentary. 



Type III, C, senile. 



RIGHT FEMUR OF A WHITE MALE. NO. 242, OR. MED. COLL. 



Pl. 31, Fig. 394. Syn. Tab. X 



Antero-posterior diameter of bone, 32 mm.; lateral, 27 mm. 

 Antero-posterior diameter of medullary canal, 19 mm.; lateral, 15 mm. 

 The medullary canal is full. Medullary index, 49%. 



Structure. — The external circumferential lamella? are fragmentary. Re- 

 mains of the lamellar horseshoe are found in the inner wall. 



The central ring forms nearly the whole of the section and is composed of 

 Haversian systems, many of which show senile changes. 



The internal circumferential lamella? form a narrow ring around the medul- 

 lary canal. 



Type III, C, senile. 



