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SMITHSONIAN CONTRIBUTIONS TO KNOWLEDGE 



vol. 35 



the lamellar and Haversian system band is a central ring' of regular Haversian 

 systems, well developed. 



The internal circumferential lamella 3 form a wide band in the lateral and 

 posterior wall. In the posterior, outer lateral wall several lamina? extend 

 obliquely from the interior of the wall to the medullary surface. The external 

 half of the posterior ridge is composed of Haversian systems, between which 

 is bone substance with many oval lacuna?, while the medullary half is composed 

 of Haversian systems with a little inter-Haversian lamella?. 



Type I-II-III, la, C, senile. 



LEFT FEMUR OF A WHITE MALE. NO. 100, CR. MED. COLL. 



Pl. 32, Fig. 410. Syn. Tab. X 



Antero-posterior diameter of bone, 24 mm. ; lateral, 31 mm. 

 Antero-posterior diameter of medullary canal, 17.5 mm. ; lateral, 13.5 mm. 

 The medullary canal is full. Medullary index, 46%. 



Structure. — The external circumferential lamella? form the boundary of a 

 part of the outer wall. In some places, however, Haversian systems form the 

 external boundary. In the outer wall lamina? separate the Haversian systems 

 of the central ring. Their lacuna? are well developed. 



The central ring constitutes the greater part of the section, and especially 

 is this true of the outer wall. 



In the inner wall is a wide external band of lamina? and oblong Haversian 

 systems extending from the posterior ridge around to the outer antero-lateral 

 junction. In the anterior wall is a wide band of lamella 1 . The systems are large, 

 small, and irregular in shape. Ln those around the medullary canal, senile 

 changes appear. The internal circumferential lamella? form an extremely nar- 

 row ring around the medullary canal. 



Type I-II-III, C, senile. 



RIGHT FEMUR OF A WHITE FEMALE. NO. 150, MED. DEPT. NORTHWESTERN UNIV. 



Pl. 32, Fig. 411. Syn. Tab. X 



Antero-posterior diameter of bone, 26 mm. ; lateral, 26 mm. 

 Antero-posterior diameter of medullary canal, 20 mm. ; lateral, 21 mm. 

 The medullary canal is full. Medullary index, 16%. 



Structure. — The section is irregular in shape and is composed of a back- 

 ground of lamella?, in which are irregularly shaped Haversian systems with 

 senile changes. 



Type I-III, C, senile. 



