278 8. W. Williston — Hind Limb of Protostega. 



one more not recovered. They are all rounded and flattened. 

 The largest, apparently the tibiale, shows a thickened carti- 

 laginous border on three sides, elsewhere thinned. The next 

 larger tarsal, probably the fibulare, is somewhat thicker, and 

 has the thickened cartilaginous surface encompassing nearly 

 the border. The third bone, the smallest, and probably 

 belonging in the distal row, is a more thickened nodular bone, 

 oval in shape with one side much thickened for cartilage. 



The metatarsal of the first toe is a thin, broad, hatchet- 

 shaped bone, with a proximal thickened articular border for 

 union with the tarsus, a smaller distal surface for phalangeal 

 articulation, a thickened, concave inner border and a strongly 

 convex, thin, outer border. 



The three metatarsals belonging to the second, third and 

 fourth toes are moderately slender, with the extremities mod- 

 erately expanded. Their relative positions I cannot give 

 positively, but I have arranged them in the figure as they 

 would seem to belong. They differ only a little in length ; 

 two of them have one border nearly straight, the other con- 

 cave, while the shortest and stoutest has both borders mark- 

 edly concave. The fifth metatarsal bears no phalanges. It is 

 a slender, triangular bone flattened proximally, where it articu- 

 lates with the tarsus; curved, cylindrical and pointed distally. 

 It evidently was much divaricated in life. 



The phalanges of the first toe were three in number, the 

 first two short, thickened, with a concave proximal and con- 

 vex distal extremity. The ungual phalanx I believe to be the 

 slender pointed one of the three preserved. The other ungual 

 phalanges preserved, two in number, were less slender, one 

 much smaller than the other. One other phalanx is known, a 

 rather short and but little constricted bone, apparently belong- 

 ing in the second row. 



Measurements. 



Length of femur . 360 mm 



diameter of head _ _■ 95 



diameter of shaft .. — 60 



Length of tibia (somewhat approximate) 270 



Greatest diameters of tarsals 90, 65, 55 



Length first metatarsal - 110 



Length fifth metatarsal 130 



Lengths second, third and fourth metatarsals.- 140, 155, 170 



University of Kansas, 

 Lawrence, Kansas. 



