196 SMITHSONIAN CONTRIBUTIONS TO KNOWLEDGE VOL. 35 



RIGHT FEMUR OF A WHITE M.A[>E. NO. IGO, MED. DEl'T. NORTHWESTERN UNIV. 



Pl. 32, Fig. 405. Syn. Tab. X 



Antero-posterior diameter of bone, 1^8 mm. ; lateral, 28.5 umi. 



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



The medullary canal is full. Medullary index, 38%. 



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

 ing around the inner and a part of the anterior wall is a wide band of lamellae 

 in which are many well developed Haversian systems. The band forms the 

 entire thickness of the inner posterior wall. In the anterior outer wall the 

 band has been displaced by Haversian systems, and in the outer posterior wall 

 the lamellar band again appears. 



The central ring is composed of Haversian systems of the (C) differentia- 

 tion, many of which show senile changes. 



The internal circumferential lamelte are fragmentary. The section is about 

 half lamellae. 



Type I-III, C, senile. 



LEFT FEMUR OF A WHITE MALE. NO. 163, MED. DEPT. NORTHWESTERN UNIV. 



Pl. 32, Fig. 406. Stn. Tab. X 



Antero-posterior diameter of bone, 28 mm. ; lateral, 25 mm. 



Antero-posterior diameter of medullary canal, 15 mm.; lateral, 11.5 mm. 



The medullary canal is full. Medullary index, 32%. 



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

 ing around the external border of the inner and anterior wall is a wide band o\' 

 lamellae, intermitted by Haversian systems. The band forms about half of the 

 inner and tlie whole of the anterior wall, and is then displaced by Haversian 

 systems. The lacunar are oval and long. Around the external surface of the 

 outer wall is a narrower band of lamelkv, interrupted by canals of the (la) 

 differentiation. The central ring of the inner and outer wall is composed of 

 Haversian systems, some of which exhibit senile changes. In the posterior 

 ridge the systems are separated by lamellae with oval lacunae. The medullary 

 canal is enclosed by a narrow ring of lamellte. 



Type I-III, la, C, senile. 



RIGHT FEMUE OF A WHITE MALE. NO. 156, MED. DEPT. NORTHWESTERN UNIV. 



Pl. 32, Fig. 407. Syn. Tab. X 



Antero-posterior diameter of bone, 31 mm. ; lateral, 23.5 mm. 

 Antero-])osterior diameter of medullary canal, 11 mm.; lateral, 11 mm. 

 The medullary canal is full. Medullary index, 20%. 



