NO. 3 COMPARATIVE HISTOLOGY OF FEMUR FOOTE 79 



Structure. — The section is composed of concentric lamellae with oval lacunae 

 and straight canalicnli surrounding the medullary canal. The lamellae are dimlj^ 

 sepai'ated into wide external and narrow internal rings by a condensation of 

 the lacunae around the medullary canal. Twofold division. 



Type I. 



LEFT FEMUR OF EPOMOPHORUS WAHLBERGII. NO. ll.")^')!, U. S. NAT. MUS. 



Pl. 8. Fig. 125. 8yx. Tah. IV 



Antero-posterior diameter of bone, '2 mm. ; lateral, 1 mm. 



Antero-posterior diameter of medullary canal, 1 mm.; lateral, U.5 mm. 



The medullary canal is full. Medullary index, 33%. 



Strvcture. — The section is composed of lamellae divided into three con- 

 centric rings. The external is narrow and composed of lamellae with long lacunas 

 and straight canaliculi; the central is wide and consists of lamellfe with oval 

 lacunae and bushy canaliculi ; and the internal is narrow and composed of lamella" 

 with long lacunar and straight canaliculi. Tlie bone sliows the threefold division. 



Type I. 



LEFT FEMUR OF GEOSSOPHAGA ELONGATA. NO. 102107, U. S. NAT. MUS. 



Pi.. 8, Fig. 126. Syn. Tab. IV 



Antero-posterior diameter of bone, 0.9 mm. ; lateral, 0.8 mm. 

 Antero-posterior diameter of medullarj" canal, 0.4 mm.; lateral, 0.4 mm. 

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



Structure.— The section is composed of concentric lamellae with oval lacuna" 

 and straight canaliculi surrounding the medullary canal. The bone is uniform. 

 Type I. 



LEFT FEMUR OF NYCTALUS AVIATOR. NO. 102098, U. S. NAT. MUS. 



Pl. 8. Fifi. 127. Syn. Tats. IV 



Antero-posterior diameter of bone, 1.5 mm. ; lateral, 1.5 mm. 

 Antero-posterior diameter of medullary canal, 0.5 mm. ; lateral, 0.5 mm. 

 The medullary canal is full. Medullary index, 12%. 



Structure. — The section is composed of concentric lamellae with oval lacunae 

 and straight canaliculi surrounding the medullary canal. The bone is uniform. 

 Type I. 



LEFT FEMUR OF SCOTOPHILUS HEATHII. NO. 13692, U. S. NAT. MUS. 



Pl. 8, Fig. 128. Syn. Tab. IV 



Antero-posterior diameter of bone, 2 mm. ; lateral, 1.5 mm. 

 Antero-posterior diameter of medullary canal, 1.2 mm.; lateral, 1 mm. 

 The medullary canal is full. Medullary index, 65%. 



