134 



SMITHSONIAN CONTRIBUTIONS TO KNOWLEDGE 



VOL. 35 



Structure. — A wide horseshoe band of laminae surrounds the bone with the 

 exception of the posterior ridge. The inner and outer portions of the posterior 

 wall are composed entirely of laminae. The anterior and lateral walls are about 

 one half lamina?. The lamina? are long and short, have oval lacuna? and bushy 

 canaliculi. The central ring is incomplete. It is composed of a crescent of well 

 developed Haversian systems in the anterior and lateral wall. The systems are 

 separated by short, oblique lamella?. The posterior ridge is composed of Haver- 

 sian systems of the (lb) differentiation, between which lamella? with oval lacuna j 

 are prominent. 



The internal circumferential lamella? are fragmentary. The bone shows 

 differentiation of structure in its lamina? and systems. 

 Type II-III, lb, C. 



LEFT FEMUR OF FELIS CONCOLOR. PANTHER. NO. 1492, AMER. MUS. NAT. HIST. 



Pl. 18. Fig. 268. Syn. Tab. YII 



Antero-posterior diameter of bone, 16 mm.; lateral, 19 mm. 

 Antero-posterior diameter of medullary canal, 11 mm.; lateral, 12 mm. 

 The medullary canal is full. Medullary index, 76%. 



Structure. — The external circumferential lamella? appear only in the pos- 

 terior and in the inner lateral Avail. The central ring constitutes the principal 

 part of the section. In the inner anterior wall the ring is divided into two equal 

 portions by a narrow concentric lamina. The ring is composed of well de- 

 veloped Haversian systems. The internal circumferential lamella? form a ring 

 of varying widths around the medullary canal. It is widest in the outer wall. 



Type I-II-III, C. 



LEFT FEMUR OF GULO LUSCUS. WOLVERENE. NO. 22884, AMER. MUS. NAT. HIST. 



Pl. 18, Fig. 269. Syn. Tab. VII 



Antero-posterior diameter of bone, 10 mm.; lateral, 11.5 mm. 

 Antero-posterior diameter of medullary canal, 5.5 mm. ; lateral, 6 mm. 

 The medullary canal is full. Medullary index, 31%. 



Structure. — A wide ring of lamella? and. crude lamina? interrupted by Ha- 

 versian systems surrounds the section with the exception of a small portion of 

 the outer wall. It is frequently crossed by canals. The lacuna? are long and 

 the canaliculi are straight. 



The central ring is somewhat incomplete and composed of well developed 

 Haversian systems. It reaches the surface in the outer wall. A ring of lamina? 

 interrupted by a few Haversian systems surrounds the medullary canal. 



Type I-II-III, C. 



