52 SMITHSONIAN COXTRIBTTIOSS TO KNOWLEDGE VOL. 35 



terior wall the canals are circular in cross-section, elsewhere tliey are long. The 

 bone shows a little differentiation of structure. 

 Type I-III, Ta. 



RIGHT fEMUK OF HELODERMA SUSPECTUM. GILA MONSTEK. NO. 583, 



AMER. MUS. NAT. HIST. 



PL. 4, Fig. 50. Stn. Tab. II 



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



Antero-posterior diameter of medullary canal, 0.7 mm. ; lateral, 0.7 mm. 



The medullary canal is full. Medullary index, 5fo. 



Structure.— The section is composed of concentric lamelte having oval and 

 long lacunsB with l)ushy and straight eanaliculi indistinctly outlined in laminae. 

 The external lamellae show long lacume and rather straight eanaliculi, the re- 

 maining lamellae, oval lacunae and bushy eanaliculi. Around the medullary 

 canal is an enclosing ring of lamellae with lacunje and long, straight eana- 

 liculi. The bone shows traces of differentiation into the three main divisions 

 — external, a central ring, and internal circumferential lamella?. Tliere is no 

 trace of an Haversian system. 



Type I. 



RIGHT FEMUR OF SCELOPORXJS CLARKII. NO. I 61 17, II. B. NAT. MUS. 



Pl. i. Fig. ol. Syx. Tap,. II 



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 lamellte with oval lacunae 

 and bushy eanaliculi surrounding the medullary canal. There is no differentia- 

 tion of structure. The section is uniform. 



Type I. 



RIGHT FEMUR OF SCELOPORUS SPINOSUS FLORIDANUS. XO. I 73 12, 



U. S. NAT. MUS. 



Pl. 4, Fig. 52. Syn. Tab. II 



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 f uU. Medullary index, 12% . 



Structure. — The section is composed of concentric lamella' with long lacuu* 

 and straight eanaliculi surrounding the medullary canal. Tliere is no dif- 

 ferentiation of structure. The section is unifonu. 



Type I. 



