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SMITHSONIAN CONTRIBUTIONS TO KNOWLEDGE 



VOL. 35 



The internal circumferential lamellae surround the medullary canal, widest in 

 the outer wall. 



Type I-II-III, la, C. 



Since the lamellar and laminar structures constitute such an important 

 part of the femora of the negro, No. 248674, it was thought best to examine 

 sections of all of the long bones of this negro in order to ascertain, if possible, 

 whether or not the lamellar and laminar structures are accidental or char- 

 acteristic of all the long bones of that individual. The following long bones 

 have, therefore, been examined: Tibia and fibula, radius and ulna, humerus, 

 clavicle and metatarsal bone of the great toe. 



TIBIA OF NEGRO, NO. 248674, U. S. NAT. MUS. 



Pl. 24, Fig. 327. Syn. Tab. VIII 



Structure. — Beginning with the inner ridge and extending laterally in both 

 directions is a wide external band of lamellae and laminae, interrupted by Ha- 

 versian systems of the (la) differentiation. A wide external band of lamellae 

 and laminae also forms the boundary of the outer wall. The anterior and pos- 

 terior walls are mostly Haversian systems. Underneath the horseshoe is an 

 irregular central ring of Haversian systems, well developed. The internal cir- 

 cumferential lamellae are arranged in places in the form of cancellous bone. 

 The lacunae are oval and long and the canaliculi are bushy. The tibia has 

 practically the same type combination as the femur. 



Type I-II-III, la, C. 



FIBULA OF NEGRO, NO. 248674, U. S. NAT. MUS. 



Pl. 24, Fig. 328. Syn. Tab. VIII 



Structure. — A wide lamellar and laminar band, interrupted in places by 

 Haversian systems of the (la) and (C) differentiations, surrounds the bone, 

 excepting the anterior wall where the Haversian systems form the circum- 

 ference. The band is widest in the posterior wall. Underneath the band is an 

 irregular ring of Haversian systems well developed. The lacunae are oval and 

 long. The internal circumferential lamellae form the boundary of the medullary 

 canal and are thickest in the posterior wall. The bone shows the same struc- 

 ture as the femur. 



Type I-II-III, la, C. 



ULNA OF NEGRO, NO. 248674, U. S. NAT. MUS. 



Pl. 24, Fig. 329. Syn. Tab. VIII 



Structure. — -The section is surrounded — posterior ridge excepted — by a 

 wide horseshoe of lamella?, interrupted by Haversian systems of the (la) and 



