NO. 3 



COMPARATIVE HISTOLOGY OF FEMUR FOOTE 



171 



all of the bone. A few senile systems appear. In the outer posterior wall 

 elongated systems occur. The Haversian systems generally are separated by 

 short lamellae with oval lacunae. The internal circumferential lamellae, of vary- 

 ing widths and irregularities, crossed by radiating canals and interrupted by 

 Haversian systems, surround the medullary canal. 

 Type I-III, la, C. 



RIGHT FEMUR OF A CHICAMA VALLEY INDIAN OF PERU. NO. 3, U. S. NAT. MUS. 



Pl. 26, Fig. 348. Syn. Tab. IX 



Antero-posterior diameter of bone, 27 mm. ; lateral, 25 mm. 

 Antero-posterior diameter of medullary canal, 16 mm. ; lateral, 11 mm. 

 Medullary index, 35%. 



Structure. — The external circumferential lamellae are incomplete. The cen- 

 tral ring constitutes most all of the section and is composed of large, small, and 

 irregularly shaped Haversian systems, between which are some inter-Haversian 

 lamellae with oval lacunae. The lamellae are most prominent in the anterior wall, 

 and here the systems are somewhat elongated in cross-section. 



The internal circumferential lamellae are fragmentary. 



Type I-III, C. 



RIGHT FEMUR OF A CHICAMA INDIAN. NO. 1, U. S. NAT. MUS. 



Pl. 26, Fig. 349. Syn. Tab. IX 



Antero-posterior diameter of bone, 26.5 mm. ; lateral, 31 mm. 

 Antero-posterior diameter of medullary canal, 11 mm. ; lateral, 16 mm. 

 Medullary index, 27%. 



Structure. — The external circumferential lamellae are fragmentary. The 

 central ring constitutes nearly all of the section and is composed of Haversian 

 systems, large, small, and irregular. In the outer wall they have a more or 

 less elongated shape arranged concentrically and separated by short lamellae 

 with oval lacunae. 



The posterior ridge is composed of Haversian systems with inter-Ha- 

 versian bone substance and oval lacunae. 



A ring of internal circumferential lamellae surrounds the medullary canal. 

 Type III, C. 



LEFT FEMUR OK A CHICAMA INDIAN. NO. 4, U. S. NAT. MUS. 



Pl. 26, Fig. 350. Syn. Tar. IX 



Antero-posterior diameter of bone, 30 mm. ; lateral, 28 mm. 

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

 Medullary index, 52%. 



