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SMITHSONIAN CONTRIBUTIONS TO KNOWLEDGE 



VOL. 35 



Internal circumferential lamellae form a very irregular boundary of the 

 medullary canal. The lacuna? are long and their canaliculi are very numerous 

 and branching. 



Type I-III, C. 



FEMUB OF CANIS LUPUS. WOLF 



Pl. 20, Fig. 289. Syn. Tab. VII 



Antero-posterior diameter of bone, 16.5 mm. ; lateral, 7 mm. 

 Antero-posterior diameter of medullary canal, 10 mm. ; lateral, 5 mm. 

 The medullary canal is full. Medullary index, 77%. 



Structure. — Beginning on both sides of the posterior ridge and extending 

 around the two lateral portions of the wall of the bone are two wide bands of 

 lamina?, interrupted by Haversian systems of the (la) and (C) differentiations. 

 As the bands reach the anterior wall the lamina? are reduced to a narrow rim of 

 external circumferential lamella?. Beginning on both sides of the posterior 

 wall, directly underneath the internal circumferential lamella? and extending 

 around the anterior wall, is a central crescent of well developed Haversian 

 systems. Bordering the medullary surface of the anterior wall is an area 

 of lamina?. The posterior ridge is composed of well developed Haversian sys- 

 tems. A narrow lamina surrounds the medullary canal. 



Type II-III, la, C. 



RIGHT FEMUB OF FELIS LEO. LION. AMEB. MUS. NAT. HIST. 



Pl. 20, Fig. 290. Syn. Tab. VII 



Antero-posterior diameter of bone, 26 mm. ; lateral, 25.5 mm. 

 Antero-posterior diameter of medullary canal, 13 mm. ; lateral, 11.5 mm. 

 The medullary canal is full. Medullary index, 28%. 



Structure. — The section is partly surrounded by a band of lamella? and 

 crude lamina?, interrupted by Haversian systems of the (la) and (C) differen- 

 tiations. The band is broken at the posterior ridge and outer antero-lateral 

 wall by Haversian systems of the central ring. 



The central ring occupies the posterior wall and the remainder of the 

 section excepting that part immediately surrounding the medullary canal. It 

 is composed of well developed Haversian systems, which are separated into two 

 nearly equal portions by a narrow laminar extension of the wide band of the 

 inner lateral wall. 



The internal circumferential lamella? form a narrow ring around the medul- 

 lary canal. Immediately behind this, in the outer anterior wall, are a number 

 of spaces. 



Type I-II-III, la, C. 



