1158 Marvels of the Untverse 
Now and then one may be seen to dart for- 
ward, seize a floating particle and resume its 
place in the school, but they never seem to 
leap out of the water to snatch at insects, and 
rarely, if ever, to dive in search of small crus- 
tacea or other minute organisms. But a more 
careful investigation into the food and manner 
of life of Anableps is certainly necessary before 
we can hope to gain any real insight into the pur- 
pose and use of this extraordinary eye. Since it 
constantly swims at the surface, with the upper 
half of the eye above water, we must assume 
that this ability to survey the upper world is 
of vital importance to its well-being. It would 
seem that the greater part of its food must con- 
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of the eyes which practically doubles them the water, rather than of organisms beneath. 
Many attempts have been made to explain the origin of this wonderful eye, but there seems to 
be no need to seek for any better explanation than that afforded by natural selection and 
variation. How the variation possibly arose is a theme which cannot be discussed in the space at 
our disposal. But it is significant to note that one of the Blennies, Dialommus, a marine species 
from Panama, displays an exactly similar eye and a similar mode of life. 
[By 7. Carreras. 
FOUR-EYED FISH. 
The fore-parts of the fish are here shown on a larger scale 
But Anableps, the double-eyed, has yet other features of interest. The sexes differ conspicuously 
in size, the males being the smaller. The females bring forth living young, instead of eges. After 
birth the young are said to be carried about by the mother in a thin-skinned bag divided by a 
partition, and thus enclosed, they remain until able to fend for themselves. 
SES 
By permission of} [Pearson’s Oil-fieli 
PART OF A MEXICAN OIL-FIELD. 
In parts of America the deposits of petroleum are so vast and under such great pressure that any well sunk into them is 
converted into a fountain whose outflow forms lakes of oil, as here shown. 
