134 SMITHSONIAN CONTRIBUTIONS TO KNOWLEDGE VOL. 35 



Structure. — A wide horseshoe band of lamina" snrronnds the bone with the 

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

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

 one half lamina?. The laminae 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 hileral wall. The systems are 

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

 sian systems of the (lb) difCerentiation, between which hnnellie with oval lacuna^ 

 are prominent. 



Tlie internal circumferential lamellae are fragmentary. The bone shows 

 differentiation of structure in its lamina^ and systems. 



TyiJc IT-HI, lb, C. 



LEFT FEMTTR OF FELIS CONCOLOR. PANTHER. NO. 1492, AMER. MI'S. NAT. HIST. 



Pl. is. Fig. 3(iS. Svx. Tail VII 



.\_nter()-])os1eri(ir (liainctci' ot Ixmc, 1(1 luiii.; lateral, 19 nun. 



Antero-postcrinr diameter of niedulhii-y canal, 11 nnn. ; lateral, ll! unn. 



The medullary canal is full. Medullary index, "(!%. 



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

 terior and in the inner lateral wall. The central ring constitutes the ])rincipal 

 part of the section. In tlie inner anti'vior wall the I'ing is divided into two equal 

 portions by a nari'ow conccnti'ic lamina. "^Flie I'ing is composed of well de- 

 veloped Ha\ersian systems. '^I'lic inlciiial circuniferential lamellae form a I'ing 

 of varying widths around tlie nicthillar\ canal. It is widest in the outer wall. 



Tyi)e T-II-III. ('. 



LEFT FEMUR OF GULO LUSCUS. WOLVERENE. NO. 22884, AMER. MUS. N.\T. HIST. 



Pl. 18. Fig. 209. 8yx. Tab. VI F 



Antero-posterioi- diameter of bone, 10 nun.; lateral, 11..") mm. 



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



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 fre(iucntl> crosseil hy canals. The lacume are long and 

 tlie canaliculi ai-e straight. 



The central ring is sonicwiiat 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. 



