iUU SMITHSONIAN COXTKIBl TIUXS JO KNUWLEDGE VOL. oO 



laiuellii' form tlic wliole tliickuess of the anterior wall with IIk- cxceptit)!! of 

 Ili(^ internal eircninfereutial lamella'. 



'i'lie internal circnml'erential lamella', with a lon^'. narrow creseeut of Ha- 

 versian systems of the (lb) differentiation, esi)ecially in the posterior and 

 adjacent lateral wall, surromid tbe medullary canal. 



Type I-III, la, lb. 



LEFT FEMUR OF MANIS. SCALY ANT-EATER. AMER. MUS. NAT. HIST. 



Pl. 10, Fici. VJo. Syn. Tab. V 



Autero-posterior diameter of bone, 7.5 mm.; lateral, 11 mm. 



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



The medullary canal is full. Medullary index, 74:%. 



St rnctvre.— The three divisions ai)pear indistinctly marked. The external 

 ciicnnifereutial lamella' witli long- lacuna' aixl straight caualiculi form a wide 

 hand aiduiid the section. They are interrupted by crude Haversian systems 

 (if the (la) differentiation and crossed by canals which assume a radial direc- 

 tion. Under this band is a narrow ring of lamella? with oval lacunae and bushy 

 canaliculi. Beneath tliis again is a narrow ring of Haversian systems of the 

 (lb) differentiation. Tlie lacuiue are oval and long aud the canaliculi are bushy. 



Internal circumferential lamella* form a narrow ring arouud the medullary 

 canal. Their lacunae are oval. In the outer wall tendon insertions and crude 

 systems are found. Threefold division. 



Type I-III, la, lb. 



RIGHT FEMXJE UF I'KOCAVI A CAPENSIS. CONEY. NO. 3532G, A.MER. JIUS. NAT. HIST. 



Pl. 10. Fig. 1;)4. Syx. Tab. V 



Autero-posterior diameter of bone, 7.5 mm.; lateral, 5 mm. 



Autero-posterior diameter of medullary canal, 3 mm.; lateral, 2.5 mm. 



The medullary canal is full. Medullary index, 25%. 



Stnictiiie. — The external circumferential lamella? form a narrow boundary 

 (if 1lu' posterior wall and then gradually widen to form the whole of tlie anterioi- 

 wall. They are interrupted by Haversian systems of the (la) differentiation. 



Their lacuiue are long and their canaliculi are straight. In the posterioi' 

 half of the section the central ring borders the medullary surface of the pos- 

 terior and inner wall and is discontinued as it reaches the anterior wall. It is 

 coniiiosed of well develo))ed Haversian systems. Internal circumferential la- 

 melhe form a broken ring ardund the medidlary canal. 



Type T TIT Ta, C. 



