78 SMITHSONIAN CONTRIBUTIONS TO KNOWLEDGE VOL. 35 



Structure. — The section is flattened antero-posteriorly and is surrounded 

 by external circnimferential lamellae. The central ring is widest and is com- 

 posed of oval lacuufe with very delicate bushy eanaliculi. The posterior wall 

 has two ridges. Tn the outer ridge is a vascular canal. The bone shows the 

 threefold division. 



Type I. 



LEFT FEMUR OF LEPTONYCTERIS. NO. 105129, U. S. NAT. MUS. 



Pl. 8, Fig. 121. Syn. Tab. IV 



Antero-posterior diameter of bone, 1 mm. ; lateral, 0.8 mm. 



Anteroposterior diameter of medullary canal, 0.5 mm.; lateral, 0.4 mm. 



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



Structure.- — The section is composed of concentric lamellae divided into wide 

 external and narrow internal rings. The external is composed of lamellffi with 

 oval lacunae and bushy eanaliculi, and the internal, of lamellte with long, narrow 

 lacunae and straight eanaliculi. Tlie bone has the twofold division. 



Type I. 



RIGHT FEMUR OF RHINOPOMA. (PALESTINE.) NO. 122140, U. S. NAT. MUS. 



Pl. 8, Fig. 132. Syx. Tab. IV 



Antero-posterior diameter of bone, 1 mm. ; lateral, 0.9 mm. 

 Antero-posterior diameter of medullary canal, 0.5 mm. ; lateral, 0.4 mm. 

 The medullary canal is full. Medullary index, 29%. 



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

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

 Type I. 



left femur of eeophylla bombifrons. no. 86262, u. s. nat. mus. 

 Pl. 8, Fig. 123. Syn. Tab. I\ 



Antero-posterior diameter of bone, 1 mm. ; lateral, 0.8 mm. 

 Antero-posterior diameter of meduUaiy canal, 0.5 mm. ; lateral, 0.4 mm. 

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



Structure. — The section is composed of concentric lamelhe with oval lacun* 

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

 Type I 



LEFT FEMUR OF PHYLLOSTOMA HASTATUM. NO. 102906, I'. S. NAT. MUS. 



Pl. 8, Fig. 124. Syn. Tab. IV 



Antero-posterior diameter of bone, 2.5 mm. ; lateral, 1.5 mm. 

 Antero-posterior diameter of medullary canal, 1.5 mm.; lateral, 1 mm. 

 The medullary canal is full. Medullary index, 64%. 



