INSTITUTE OF SCIENCE, PHILADELPHIA. 



35 



Circumference of shaft where narrowest, 

 Transverse diameter " " 



Fore and aft " 



236 mm. 

 92 " 



54 " 



In comparison with two tibiae of Mylodon Jiarlani, from Missouri, re- 

 ferred by Dr. Harlan to the Oryctcrothcriiini missoitncnsc, in "A Description of 

 the Bones of a New Fossil Animal of the Order Edentata," American Jour- 

 nal of Science and Arts, 1843, ^9) the corresponding measurements are as 

 follows : 



Total length 



Transverse diameter proximal extremity, 



distal 

 Circumference at middle of shaft, . 



Louisiana specimens. 



10 in. 



/Tf) 



t3 " 

 D 1 



9^" 



Missouri specimens. 



10 in. loi/^ in. 



5t\" 6^ " 

 5 " S'A " 



lOr- 



ITT 



In comparison with the tibia of Mylodon robustiis, as described in Prof. 

 Owen's memoir, the measurements are as follows ; 



Mylodon harlani. 



M. robustus. 



Greatest length along the middle, . 

 Smallest circumference of the shaft, 

 Breadth of proximal articular surface, 

 " distal 



10 in. 8 in. 6 lines. 



9 " 5 lines. 8 " 6 " 



7 " 6 " 6 " 



4 " 6 " 4 " 6 " 



The ungual phalanx, represented in figure 2, plate V., resembles that of 

 the second toe of the hind foot of Mylodon robnstiis, as seen in Prof 

 Owen's figures in the work above indicated. It pertains to the largest of 

 the four toes of the foot. The specimen has its osseous sheath of the nail 

 broken away, except the root or base. The lower part of this extends nearly 

 half the length of the bone beneath. The matrix of the claw is thick and 

 transversely convex above as well as in the length. The measurements of 

 the specimen are as follows : 



Extreme length to the end of the bone, 

 Depth obliquely at the proximal extremity, 

 Transverse breadth at the " " 



166 mm. 

 65 " 

 50 " 



In comparison with the corresponding phalanx of Mylodon robustus as 

 given in Prof Owen's memoir, the measurements are as follows : 



Length, .... 

 Greatest height near middle. 

 Circumference " " 



Breadth " " . 





M. harlani. 





M. robustus. 



6 



in. 8 



lines. 



5 



in. 4 lines, 



2 



" 2 



n 



I 



" 10 " 



6 



" 2 



(t 



6 



" 3 " 



I 



" 3 



it 



I 



" 9 " 



