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SMITHSONIAN CONTRIBUTIONS TO KNOWLEDGE 



VOL. 35 



lamella 1 . The crescent nearly encircles the bone. The Haversian systems are 

 well developed, their lacunae are oval, and their canaliculi are relatively few. 

 Their canals frequently unite. In some places bands of lamella; cross the 

 crescent extending from the outer to the inner lamellae. Numerous canals 

 traverse the crescent. The internal circumferential lamellae form a wide, irregu- 

 lar ring, fusing with the external lamella 1 in the anterior wall. The lacunae 

 are long and narrow and their canaliculi are long and branching. 

 Type I-III, C. 



LEFT FEMUR OF CRYPTOPROCTA FEROX. CAT-LIKE CIVET. AMEK. MUS. NAT. HIST. 



Pl. 14, Fig. 235. Syn. Tab. VI 



Antero-posterior diameter of bone, 8.5 mm. ; lateral, 8 mm. 

 Antero-posterior diameter of medullary canal, 4.5 mm. ; lateral, 4.5 mm. 

 The medullary canal is full. Medullary index, 42%. 



Structure. — The section is surrounded by a ring of external lamellae of 

 varying widths. It is interrupted by numerous canals of the (la) differentia- 

 tion. The lacunae are long and the canaliculi are straight. The ring is distinct 

 from the underlying central ring of Haversian systems, which are well devel- 

 oped. The medullary canal is surrounded by internal circumferential lamellae 

 of varying widths. 



Type I-III, la, C. 



RIGHT FEMUR OF HYiENA CKOCUTA. HYJ3NA. NO. 35431, AIM ER. MUS. NAT. HIST. 



Pl. 14, Pig. 2'M\. Syn. Tab. VI 



Antero-posterior diameter of bone, 14 mm.; lateral, 18 mm. 

 Antero-posterior diameter of medullary canal, 9 mm. ; lateral, 13.5 mm. 

 The medullary canal is full. Medullary index, 98%. 



Structure. — External lamellae form a wide ring around the section with the 

 exception of the outer ridge. The lamellae are crossed by canals, interrupted by 

 crude Haversian systems of the (la) differentiation, and have long lacunae and 

 straight canaliculi. 



The central ring is composed of well developed Haversian systems with 

 some inter-Haversian lamellae. The systems form the whole of the outer ridge, 

 where they are separated by bone substance with many oval lacunae and bushy 

 canaliculi. 



A narrow ring of internal circumferential lamellae surrounds the medullary 

 canal. The lacunae are long. 

 Type I-III, la, C. 



