220 
Thus the broods of 94° in Turkey Lake differs from the broods of the preced- 
ing and succeeding year in the number of scales in the lateral line and in the 
number of dorsal spines, and the broods of 95° in Tippecanoe Lake differ from 
the broods of 96° in the number of dorsal rays. In regard to the former, I have 
already remarked that ‘‘the difference in the dorsal spines may possibly be due 
to the presence of local races in the lake. While this may possibly be the case, it 
is not at all probable, because, in the first place, the curve constructed for the 
dorsal spines of 100 specimens of the brood of ’93° taken within a distance of 100 
ae 
55 = 
Fie. 4. 
yards along the shores where the conditions were undoubtedly uniform, gave a 
curve identical with that for all the broods of ’93°. In the second place, the ’93° 
and 794° specimens are found in about equal abundance together, and since these 
were promiscuously preserved it is altogether probable that from any given locality, 
an equal number of each brood was taken.” 
I have since examined a considerable number of specimens from three distant 
localities in the lake, and find that they do not present sufficient local differences 
to account for these occurring in the different broods. 
In regard to the broods in Tippecanoe Lake it need.but be said that they were 
of the same age and were collected from the same place in the lakes. 
15—ScIENCE. 
