NO. 3 



COMPARATIVE HISTOLOGY OF FEMUR FOOTE 



137 



LEFT FEMUR OF GAZELLA GRANTI. GRANT 's GAZELLE. NO. 27762, AMER. MUS. NAT. HIST. 



Pl. 18, Fig. 275. Syn. Tab. VII 



Antero-posterior diameter of bone, 19 mm.; lateral, 19.5 mm. 

 Antero-posterior diameter of medullary canal, 10.5 mm.; lateral, 11 mm. 

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



Structure. — The section is composed of a wide horseshoe band of lamina? 

 embracing the posterior ridge. In the anterior wall they are interrupted by 

 Haversian systems, especially near the circumference. They are long and short 

 and their lacunae are round and oval with bushy and straight canaliculi. Under- 

 neath the laminae of the outer lateral, the anterior, and inner lateral wall is a 

 crescent of Haversian systems well developed. The posterior ridge is com- 

 posed mostly of Haversian systems. Internal circumferential lamellae with 

 narrow lacunae and straight canaliculi surround the medullary canal. 



Type II-III, C. 



LEFT FEMUR OF KOBUS ELLIPSIPRYMNOS. WATER BUCK. NO. 27669, 



AM EH. MUS. NAT. HIST. 



Pl. 18. Fig. 276. Syn. Tab. VII 



Anteroposterior diameter of bone, 28 mm.; lateral, 25 mm. 

 Antero-posterior diameter of medullary canal, 18 mm. ; lateral, 16 mm. 

 The medullary canal is full. Medullary index, 70%. 



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

 ing around the outer and anterior wall is an external band of lamellae, inter- 

 rupted by Haversian systems of the (la) differentiation and by canals. Their 

 lacunae are long and their canaliculi are straight. The inner wall of the section 

 is composed of lamina? which are continued around the section to the posterior 

 ridge under the lamellar band of the anterior and outer wall. The laminae are 

 frequently interrupted by Haversian systems. Their lacunae are long and their 

 canaliculi are straight. The posterior ridge is composed of Haversian systems 

 which are extended around the outer and anterior wall and border upon the 

 medullary canal. Their lacunae are long. 



Type I-II-III, la, C. 



RIGHT FEMUR OF ARCTOMYS MONAX. WOODCHUCK OR GROUND HOG. CR. MED. COLL. 



Pl. 19, Fig. 277. Syn. Tab. VII 



Antero-posterior diameter of bone, 6 mm. ; lateral, 7 mm. 

 Antero-posterior diameter of medullary canal, 1 mm.; lateral, 4.5 mm. 

 The medullary canal is full. Medullary index, 74%. 



Structure. — Two laminae with long lacunae and straight canaliculi, inter- 

 rupted here and there by Haversian systems of the (la) differentiation, sur- 

 round the section with the exception of the posterior ridge. 



