194 SMITHSONIAN CONTRIBUTIONS TO KNOWLEDGE VOL. 35 



LEFT FEMUR OF A WHITE MALE. NO. 148, MED. DEPT. NORTHWESTERN UNIV. 



Pl. 31, Fici. 401. Stn. Tab. X 



Antero-posterior diameter of boue, 24 mm.; lateral, 33 mm. 



Antero-posterior diameter of medullary canal, 13.5 mm.; lateral, 14 mm. 



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



Structure. — Remains of the lamellar horseshoe band are seen as a back- 

 ground in the lateral and anterior wall. The band is interrupted by numerous 

 Haversian systems. The central ring is incomplete and composed of large, 

 small, and irregular Haversian systems. Senile changes are frequent in the 

 anterior and posterior wall. The internal lamellae form a narrow ring around 

 the medullary canal. 



Type I-III, C, senUe. 



LEFT FEMUR OF A WHITE MALE. NO. 230, CR. MED. COLL. 



Pl. 31, Fig. 402. Syn. Tab. X 



Antero-posterior diameter of bone, 31 mm.; lateral, 29 mm. 



Antero-posterior diameter of medullary canal, 17 mm.; lateral, 14 mm. 



The medullary canal is full. Medullary index, 33%. 



Structure. — The horseshoe band of lamellae, widest in the outer and absent 

 in the anterior wall, remains as a background. It forms half of the outer 

 and one-third of the posterior inner wall. In the lamellar background are oval 

 and round Haversian systems. The central ring is composed of large, small, 

 and irregular Haversian systems. Senile changes are frequent. The lacunte 

 are generally oval. The internal circumferential lamelte appear in fragments 

 and as cancellous bone in the anterior wall. 



Type I-III, C, senile. 



LEFT FEMUR OK A WHITE MALE. NO. 97, ("K. MED. COLL. 



Pl. 32, Fig. 403. Syn. Tab. X 



Antero-posterior diameter of bone, 28..") mm.; lateral, 27 mm. 



Antero-posterior diameter of meiiullary canal, Ki mm.; lateral, 15 mm. 



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



Structure. — A wide horseshoe band of lamina; and lamella? surrounds tlie 

 section. On both sides of the ridge the heel of the shoe constitutes nearly the 

 whole thickness of tlie wall, while the toe constitutes more than one-half of 

 the anterior wall. In the inner wall the band is narrow and in the outer wall, 

 wide. On both sides of the posterior ridge the heel of the shoe is composed of 



