NO. 3 



COMPARATIVE HISTOLOGY OF FEMUR FOOTE 



135 



LEFT FEMUR OF ERIGNATIIUS BARBATUS. SEAL. NO. 19347, AMER. MUS. NAT. HIST. 



Pl. 18, Fig. 270. Syn. Tab. VII 



Antero-posterior diameter of bone, 19.5 mm.; lateral, 39 mm. 

 Antero-posterior diameter of medullary canal, 30 mm.; lateral, 25 mm. 

 The medullary canal is full. Medullary index, 50%. 



Structure. — Three divisions are present. The external circumferential la- 

 mella? form a narrow enclosing' ring'. The lacunas are oval. 



The central ring is composed of well developed Haversian systems, short 

 lamina?, and lamella? with cross canals intermixed. It shows no plan of arrange- 

 ment, but a confusing mixture of units. The lacuna? are oval and long and the 

 canaliculi are straight. The ring constitutes nearly all of the section. The 

 internal circumferential lamella? form an incomplete ring around the medullary 

 canal. In the lateral walls the lamella? take the cancellous form. The planless 

 arrangement of its three units is somewhat significant. 



Type II-III, C. 



LEFT FEMUR OF BOS BUBALIS. WATER BUFFALO. NO. 27770, AMER. MUS. NAT. HIST. 



Pl. 18, Fig. 271. Syn. Tab. VII 



Antero-posterior diameter of hone, 48 mm.; lateral, 45 mm. 

 Antero-posterior diameter of medullary canal, 24 mm.; lateral, 25 mm. 

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



Structure. — Beginning on the inner side of the posterior and extending 

 around the inner, anterior, and a portion of the outer wall is a wide band of 

 lamina?, short and long, crossed by a great number of branching canals and 

 interrupted in the anterior and outer wall by a few Haversian systems. Under- 

 neath this band in the inner and anterior wall is a crescent of Havesian sys- 

 tems and lamella? with oval lacuna? and bushy canaliculi. The crescent is crossed 

 by numerous canals. The outer wall is composed of Haversian systems and 

 short lamina? and the posterior wall of Haversian systems and inter-Haversian 

 lamella? with oval lacuna' and bushy canaliculi. The medullary canal is sur- 

 rounded by a narrow ring of internal circumferential lamella 1 . 



Type II-III, lb, C. 



LEFT FEMUR OF OVIS MONTANA. MOUNTAIN SHEEP. CR. MED. COLL. 



Pl. 18, Fig. 272. Syn. Tab. VII 



Antero-posterior diameter of bone, 20 mm. ; lateral, 25 mm. 

 Antero-posterior diameter of medullary canal, 12.5 mm.; lateral, 15 mm. 

 The medullary canal is full. Medullary index, 60%. 



Structure. — The bone is composed of short concentric lamina? enclosing the 

 medullary canal, with the exception of the crescent of Haversian systems in 



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