140 SMITllSUXIAX COXTKIBUTTONS TO KNOWLEDGE VOL. 35 



(ii'ossed i)y radiating- cauals and interrupted by crude Haversian canals. The 

 lamellae on reaching the anterior wall separate into lamina?, which constitute 

 the whole inner wall. Here and there the canals between the laminse widen 

 into circular openings. The posterior ridge is composed of Haversian systems, 

 between which are short lamella; with round lacimfe. The intornul circum- 

 ferential lamellae surround the medullary canal. 

 Type I-II-III, la, C. 



FEMLTR OF A FOX TERKIEK (XOT A PUKE BLOOD). XO. 202, CK. MED. COLL. 



Pl. 19. Fig. 381. Syn. Tab. VII 



Antero-posterior diameter of bone, 11 mm.; lateral, 9.5 mm. 



Antero-posterior diameter of medulla ly canal, 6.5 mm.; lateral, G mm. 



The medullary canal is full. Medullary index, 59%. 



Structure. — The section is surrounded by a wide horseshoe of laminae which 

 forms three-fourths of the thickness of the wall of the bone. The canals between 

 the laminae widen at intervals into circular areas. The laminai are fre<iuentl\ 

 crossed by irregular canals. The lacuna^ are oval. The central ring is a nar- 

 row crescent and is composed of well developed Haversian systems. The ring 

 reaches the surface of the posterior ridge where it is composed of vascular 

 canals surrounded by concentric lamellae. Between the canals are long, minute, 

 tendon insertions. The internal circumferential lamellae form a narrow ring 

 around the medullar)' canal. Just behind the ring are several large vascular 

 spaces. 



Type II-III, C. 



RIGHT FEMUR OF A MONGREL DOG (nO CHARACTERISTIC FEATURES). 

 NO. 200, CR. MED. COLL. 



Pl. 19, Fig. 282. Syn. Tab. VII 



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



Antero-posterior diameter of medullary canal, 8.5 mm.; lateral, 9 mm. 



The medullary canal is full. Medullary index, 90%. 



Structure. — The section is surrounded by a horseshoe band of lamina? and 

 lamellae. The laminae form the whole width of the inner wall. They then be- 

 come fewer in number as they reach the anterior wall, where they are reduced 

 to a narrow lamellar band. The lamellte then widen and separate into lamina? 

 as the band reaches the posterior ridge. The central ring is reduced to a long, 

 narrow crescent of Haversian systems which nearly encircles the section. The 

 systems reach the surface of the posterior ridge and form nearly the whole 

 width of the posterior wall. They are well developed. The internal circum- 

 ferential lamellae do not form an enclosing ring. In the posterior wall they 

 form a narrow band, in the outer wall the band widens into laminae, and in the 



