no. 3 comparative histology of femur foote 55 



right femur of sauromalus. no. j 40 6, v. s. nat. m us. 

 Pl. 4, Fig. 61. Syn. Tab. 1 1 



Antero-posterior diameter of bone, 3 mm.; lateral, 2.5 mm. 



Antero-posterior diameter of medullary canal, 1.5 nan.; lateral, 1.2 mm. 



The medullary canal is full. Medullary index, 32%. 



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

 and straight canaliculi partially divided into concentric rings. A vascular canal 

 is seen in the posterior inner wall. A narrow ring of lamelte with long lacunae 

 and straight canaliculi surrounds the medullary canal. 



Type I. 



right femur of gerrhonotus grandis. no. i 22 4, u. s. nat. mus. 

 Pl. 4, Pig. 62. Syn. Tah. 1 [ 



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



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



The medullary canal is full. Medullary index, 11%. 



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

 long laemife and straight and bushy canaliculi. Around the i)osterior and 

 lateral medullary surface is a crescent of basic bone substance with round 

 lacuna? and bushj' canaliculi. 



Type I. 



RIGHT FEMUR OF PYTHON REGIUS. PYTHON. (114- FEET IN LENGTH 



DIED AT WASHINGTON ZOo) 



Pl. 4, Fig. 63. Syn. Tab. II 



Antero-posterior diameter of bone, 1 mm. ; lateral, 0.6 mm. 



Antero-posterior diameter of medullary canal, 0.4 mm. ; lateral, 0.3 mm. 



The medullary canal is full. Medullary index, 24%. 



Structure. — The femur is rudimentary. The section is composed of lamellae 

 arranged in a peculiar manner. In the anterior wall they are arranged con- 

 centrically around a semicircle with a short radius. In the lateral and pos- 

 terior wall the lamellae take a long curve from the medullary surface of the 

 anterior wall. The lacuna; are round and the canaliculi are bushy. The anterior 

 wall is best developed. A narrow ring of internal lamellae with long lacunae 

 and straight canaliculi surrounds the medullary canal. 



Type I. 



5 



