207 
‘ 
In no instance have I known of the Shrike attacking so large a bird 
as the Sparrow Hawk, much less one so well able to defend itself. 
Whether or not the Hawk had become entangled in the hedge before the 
attack of the Shrike is not known, but that the Hawk was impaled on the 
thorns and that the Shrike was striking it with wings and beak is certain. 
MATERIAL FOR THE StTuDY OF THE VARIATION OF ETHEOSTOMA CAPRODES 
RAFINESQUE AND ETHEOSTOMA NIGRUM RAFINESQUE IN TURKEY LAKE 
AND TIPPECANOE LAKE.* By W. J. MoENKHAUS. 
The matter contained in the present paper relates to two species of darters, 
Etheostoima caprodes and Etheostoma nigrumfrom Turkey Lake and Tippecanoe Lake. f 
The discussion is confined almost wholly to the variation in the dorsal and anal 
fins. In a few instances the scales in the lateral line and on the nape are also 
considered. The aim of this paper is to answer the following questions: 
1. Do the sexes present any differences in their variations? 
2. How do the specimens in Tippecanoe Lake differ from those of Turkey 
Lake? 
3. Is the variation in the two species determinate with the locality; 7. e., do 
both vary in the same direction in the same locality? 
4. Do the broods of one season differ from the broods of another season? 
5. Are the variations of one fin correlated with the variations in the others? 
I. DO THE SEXES PRESENT ANY DIFFERENCES IN THEIR VARIATIONS? 
Inasmuch as all the specimens upon which the comparisons are to be made 
include the two sexes, it will be advisable to first determine just what modifica- 
tions sex has upon the different structures. The specimens of Etheostoma caprodes 
* (Contributions from the Zoological Laboratory of the Indiana University under the di- 
rection of C. H. Eigenmann, No. 22. 
+ For the purpose of making a detailed comparison between the faunas of two units of 
environment, a Biological Station has been established on Turkey Lake, Kosciusko County, 
Indiana. Five miles from this lake is another lake of different shape and depth—Tippe- 
canoe Lake. The two lakes are on opposite sides-of the watershed separating the St. Law- 
rence from the Mississippi Basin. A physical survey has been made of these lakes, and as 
far as our means permit, the physical and biological conditions of the two lakes are being 
studied as two units of environment within which we wish to determine the extent of vari- 
ation in the non-migratory vertebrates, the kind of variation, whether continuous or discon- 
tinuous, the quantitative variation, the direction of variation, and the annual or periodic 
variation and the effect of selection. The present is one of a series of papers illustrating 
these points. CHeaH: 
