624 Marvels of the Universe 
appearance of having undergone amputation of the hinder end of the body. They have been 
humorously described, indeed, as “‘ cherub-fishes, because they are cut off behind”! This general 
semblance is not without a purpose : for all these fishes are dwellers at the surface of tropical seas, but 
apparently depend largely for food on prey caught at tremendous depths. The Sun-fish, we know, 
lives largely, during a part of the year, on larval eels, which can only be had in quantity 
by diving ; and in all these cases the motive power is furnished by the vibration of the dorsal 
and anal fins. Thus, then, the common likeness in contour has been brought about by adaptation 
to a common end, this peculiar shape apparently being the most suitable for sudden descent head-first. 
But even among fishes which normally swim by vigorous side-to-side, lashing movements of the tail 
there\;sare some which, on 
occasion, make use of vibra- 
tions of the dorsal, or dorsal 
and anal fins, to attain special 
ends, generally stalking prey. 
they Rikewisssonewsormthese: 
The celebrated John Dory is 
another. As everybody knows, 
the John Dory is exceedingly 
thin from side to side, and 
deep measured from _ the 
back to the belly. Thus, end 
on, he is a mere line in the 
water, and this fact serves 
him in good stead when stalk- 
ing a victim—say, a_ sprat. 
Instead of striving to over- 
take his prey with a rush, 
he approaches his victim 
warily, moving by means of 
the vibrations just referred 
to. As soon as he is suffi- 
ciently near to ensure success, 
aes & he shoots forward his wonder- 
[G. R. Balance. ful tubular mouth, and in 
A YOUNG ICE FLOWER. 
The rarefied air of the Alps holds the water-vapour in suspension, and the intense eu! instant the fish WS Gale 
cold freezes it into crystals of ice. These are attracted one to the other,and so go to eulfed and the telescopic 
create the Ice Flower. Notice the little tufts of ice near the central bloom, which will 
shortly be incorporated in the flower. 
Photo by] 
mouth goes back to its place 
again ! 
The Pipe-fish of our coasts is another fish which, like the Sea-horses, swims by means of vibra- 
tions of the dorsal fin. But this fish moves, not horizontally, after the fashion of fish, but vertically. 
And the same is true of another and much more remarkable fish. This is the Tortoise-fish, 
so called because the scales of the body have become welded together to form a_ box-like 
case, as inflexible as the shell of a tortoise, only the dorsal fin and the extreme end of the tail being 
capable of movement. This shell is almost as flat as a paper-knife, and the ventral edge is almost 
razor-like, so as to offer the least possible resistance to the water. To secure the greatest possible 
rapidity of movement in this strange position, the dorsal fin has shifted to the extreme hinder end 
of the shell, and looks at first like the tail fin, which last has become bent round, as it were, to the 
ventral or under surface! A shoal of these fish seen swimming in an aquarium has an almost 
uncanny effect, for the slender bodies are almost transparent. 
