542 On the Effect of Impacts and Strains [July, 
Mr. Wood’s specimen, and to which I ascribe the character of 
drills. 
Figure 3.—Original made of light-brown stone of chalcedonic 
appearance. Colorado. (Museum No. 9208.) 
Figure 4.—Yellowish flint. Ohio. (Museum No. 16,484.) 
Figure 5.—Gray jasper. New York. (Mus. No. 6180.) 
Figure 6.—Cast of a large implement of brownish hornstone. 
The original is in possession of Mr. L. Leppelman, of Fremont, 
Ohio. (Museum No. 35,624.) 
Figure 7.— Yellowish-brown jasper. Connecticut. (Museum 
No. 6084.) 
Figure 8.— Dark-gray hornstone. Ohio. (Museum No. 
16,484.) 
Figure 9.—Light-reddish jasper. West Virginia. (Museum 
No. 13,376.) 
Having properly hafted the original of Figure 8, I operated 
with it on a piece of an aboriginal potstone vessel, three-fourths 
of an inch in thickness, which I perforated in about twelve min- 
utes, the result being a bore not quite as regular as that exhibited 
in Mr. Wood’s specimen, but otherwise resembling it in all essen- 
tial points. The manipulation was the same as in the previously- 
described experiment by which I obtained a small bi-conical pet- 
foration. ; 
20% 
ON THE EFFECT OF IMPACTS AND STRAINS ON 
THE FEET OF MAMMALIA? 
BY E. D, COPE. 
Te principal specializations in the structure of the feet of the 
Mammalia may be summarized as follows: : 
I. The reduction of the number of the toes to one in the Per 
sodactyla (horses, etc.), and two in the Artiodactyla (cloven feet). 
II. The second hinge-joint in the tarsus of the Artiodactyla. 
1 The specimen from the Yorkshire Wolds, represented by Figure 231 0n page 29% 
of Mr. Evans’s work (Ancient Stone Implements, etc.) appears to belong to the 
same class of tools. 
* Read before the National Academy of Sciences, April, 1881. Abstract. ed 
of the points of this paper have already been discussed in the NATURALIST (April), 
but the present abstract contains additional matter. ; 
