44 SMITHSOXIAX CONTEIBUTIONS TO KNOWLEDGE VOL. OO 



ance. Around the medullary canal are a few lamella' with long lacunie and long 

 and straight canaliculi. Threefold division. 

 Type I. 



EIGHT FEMUR OF SCAPHIOPT'S HOLBROOKII. SPADEFOOT TOAD. AMER. MVS. XAT. HIST. 



Pl. 2, Fig. 28. Syx. Tab. I 



Antero-posterior diameter of bone, 1.5 mm.; lateral, 1 mm. 



Antero-posterior diameter of medullary canal, 0..) mm.; lateral, U.o mm. 



The medullary canal is full. Medullary index, 11%. 



Structure. — The section is composed of two divisions, one, external, com- 

 posed of concentric lamella; with round and oval lacuna^ and long, straight 

 canaliculi, and the other, internal, composed of circumferential lamell* with 

 long, narrow lacunae and long, straight canaliculi. Twofold division. 



Tj-pe I. 



RIGHT FEMUK OF SCAPHIOPITS COXTCHII. NO. F 50 20, U. S. X.AT. Mt'S. 



Pl. 2. Fig. 29. Syx. Tab. 1 



Antero-posterior diametei- of hone, 1 niiiL ; latei'al, 1.5 mm. 



Antero-posterior diameter of medullary canal, 0.5 mm.; lateral, 0.6 mm. 



Medullary canal is full. Medullary index, 24%. 



Structure. — The section is composed of lamellae with long lacuna^ and bushy 

 canaliculi, indistinctly divided into concentric rings which surround the medul- 

 lary canal. 



Tj-pe I. 



RIGHT FEMUR OF SCAPHIOPUS HAMMONDII. NO. F 20 6, U. S. XAT. MUS. 



Pl. 2. Fig. .30. Syx. Tab. I 



Antero-posterior diameter of bone, 1 mm. ; lateral, 0.8 mm. 



Antero-posterior diameter of medullary canal, 0.5 mm. ; lateral, 0.4 nmi. 



The medullary canal is full. Medullary intlex, 33 '/c. 



Structure. — The section is composed of concentric rings of lamelhe sur- 

 rounding a central medullary canal. The lacuna' <irc oval and the canaliculi 

 are long. 



Type I. 



right femur of pi pa americaxa. st-rixaji toad. amer. mus. nat. hist. 



Pl. .1. Fig. ?,\. Syx. Tab. 1 



Antero-posterior diamcler of bone, 3.5 nun.; lateral, 5.5 mm. 

 Antero-posterior diameter of medullary canal, 0.8 mm. ; lateral, 0.8 nun. 

 The medullary canal is full. Mednllai'y index, 3%. 



