94 



SMITHSONIAN CONTRIBUTIONS TO KNOWLEDGE 



VOL. 35 



EEMUR OF LEMUR MONGOZ. NO. 86849, U. S. NAT. MUS. 



Pl. 9, Fig. 177. Syn. Tab. V 



Antero-posterior diameter of bone, 9 mm. ; lateral, 7 mm. 

 Antero-posterior diameter of medullary canal, 7 mm. ; lateral, 4.5 mm. 

 The medullary canal is full. Medullary index, 100%. 



Structure. — The section is composed of lamella? with long lacunae and 

 straight canaliculi, divided into wide external and narrow internal rings. The 

 lamella? of the external ring are interrupted by small and rather crude Ha- 

 versian systems of the (lb) differentiation and by vascular canals which occupy 

 a concentric position in the wall of the bone. The internal ring of lamella? with 

 long lacuna? and straight canaliculi surrounds the medullary canal. The bone 

 has the twofold division. 



Type I-III, lb. 



LEFT FEMUR OF COLOBUS ABYSSINICUS CAUDATUS. NO. 27711, AMER. MUS. NAT. HIST. 



Pl. 9, Fig. 178. Syn. Tab. V 



Antero-posterior diameter of bone, 12.5 mm.; lateral, 13 mm. 

 Antero-posterior diameter of medullary canal, 7 mm. ; lateral, 7 mm. 

 The medullary canal is full. Medullary index, 43%. 



Structure. — The section is composed of a very wide band of external cir- 

 cumferential lamella?, interrupted by numerous very crude Haversian systems 

 of the (la) and (lb) differentiations. The band forms nearly the whole width 

 of the wall of the bone. In the posterior wall the lamella? are displaced by small 

 undeveloped Haversian systems and in the outer wall a narrow crescent of 

 Haversian systems of the (C) stage appears just external to the internal cir- 

 cumferential lamellae 



Internal circumferential lamella? surround the medullary canal. Generally 

 the lacuna? are long and narrow and the canaliculi are straight, but in the pos- 

 terior wall the lacuna' are oval. The bone shows the twofold division. 



Type I-III, la, lb, C. 



FEMUR OF PUTORIUS VULGARIS. WEASEL. CR. MED. COLL. 



Pl. 9, Fig. 179. Syn. Tab. V 



Antero-posterior diameter of the bone, 1.5 mm. ; lateral, 2 mm. 

 Antero-posterior diameter of the medullary canal, 1 mm. ; lateral, 1.5 mm. 

 The medullary canal contains a very thin layer of marrow around the walls 

 of the bone. Medullary index, 62%. 



