NO. 3 COMPARATIVE HISTOLOGY OF FEMUB FOOTE 157 



the peripheral portion are in pretty good condition, altliough senile changes are 

 present to some extent. 



The internal circumferential lamellae form a narrow ring around the medul- 

 lary canal. 



Type III, C, senile. 



LEFT FEMUR OF A NEGRO. NO. 224714, U. S. NAT. MUS. 



Pl. 22, Fig. 316. Stn. Tab. VIII 



Antero-posterior diameter of bone, 34 mm. ; lateral, 36 mm. 



Antero-posterior diameter of medullary canal, 21 mm. ; lateral, 21 mm. 



The medullary canal is full. Medullary index, 56%. 



Structure. — Beginning on the inner side of the posterior ridge and extend- 

 ing around the lateral to the anterior wall is one-half of the lamellar horse- 

 shoe described in the foregoing femora. The lamellar shoe is studded with 

 many Haversian systems. The central ring is narrow and composed of Ha- 

 versian systems, many of which are senile. The posterior ridge and adjoining 

 outer wall are composed entirely of Haversian systems. Internal circum- 

 ferential lamellae form a narrow ring around the medullary canal. 



Type I-III, C, senile. 



LEFT FEMUR OF A NEGRO. NO. 11, MED. DEPT. TULANE UNIV. 



Pl. 22, Fig. 317. Stn. Tab. VIII 



Antero-posterior diameter of bone, 32 mm. ; lateral, 26.5 mm. 



Antero-posterior diameter of meduUarj' canal, 13 mm. ; lateral, 12 mm. 



The medullary canal is full. Medullary index, 22%. 



Structure. — The remains of the lamellar horseshoe band are evident. It is 

 narrow in the outer posterior, widens to one- third the width of the anterior, 

 and extends along the inner wall as a wide band. The band is interrupted by 

 Haversian systems in the lateral wall and by Haversian canals of the (la) 

 differentiation in the anterior wall. The central ring is composed of well de- 

 veloped Haversian systems. The internal lamellae form a wide ring around the 

 medullary canal. 



Type I-III, la, C. 



RIGHT FEMUR OF A NEGRO. NO. 2, MED. DEPT. TULANE UNIV. 



Pl. 23, Fig. 318. Stn. Tab. VIII 



Antero-posterior diameter of bone, 30 nnn. ; lateral, 29 mm. 

 Antero-posterior diameter of medullary canal, 16 mm.; lateral, 14 mm. 

 The medullary canal is full. Medullary index, 36%. 



