458 THE HAMMER-HEADED SHARK. 
employed for many purposes. The handles of swords, where a firm hold is 
required, are sometimes bound with this substance ; and joiners use it in 
polishing the surface of fine woods so as to bring out the grain. It is also 
employed instead of sand-paper upon match-boxes. 
The egg of this species is very curious in form and structure, and is often 
found on the sea-shore, flung up by the waves, 
especially after a storm. These objects are 
familiar to all observant wanderers by the sea- 
shore, under the name of mermaid’s purses, 
sailors purses, or sea purses. Their form is 
oblong, with curved sides, and at each angle there 
is a long tendril-like appendage, having a strong 
curl, and in form not unlike the tendrils of the 
vine. The use of these appendages is to enable 
the egg to cling to the growing seaweed at the 
bottom of the ocean, and to prevent it from being 
washed away by the tide. 
For the escape of the young shark, when strong 
enough to make its own way in the wider world 
of waters, an outlet is provided in the opened end 
of the envelope, which opens when pushed from 
within, and permits the little creature to make 
its way out, though it effectually bars the entrance 
against any external foe. 
The head of the Little Dog-fish is rather flat 
upon the top, there is a little spiracle or blow-hole 
behind each eye, and the shape of the mouth is 
somewhat like a horse-shoe. The general colour 
of the body is pale reddish on the upper parts, 
covered with many little spots of dark reddish 
brown; below it is yellowish white. The length of 
this species is about eighteen inches. The colour 
is beautiful slate-blue above, and white below. 
THE remarkable fish depicted in the illustration 
affords a striking instance of the wild and won- 
drous modifications of form assumed by certain 
creatures, without any ascertained purpose being 
gained thereby. We know by analogous reasoning 
that some wise purpose is served by this astonish- 
ing variation in form; but as far as is yet 
known there is nothing in the habits of this spe- 
cies that accounts for the necessity of this strange 
shape. 
The shape of the body is not unlike that a we 
enerality of sharks, but it is upon the head that 
Egg of Dog-fsh, ie aieiben is at once paced As may be seen 
from the figure the head is expanded laterally in a 
most singular manner, bearing, indeed, no small resemblance to the head of 
a hammer. The eyes are placed at either end of the projecting extremities, 
and the mouth is set quite below, its corners just coinciding with a line 
drawn through the two projecting lobes of the head. 
This species attains to a considerable size, seven or eight feet being a 
common measurement, and specimens of eleven or twelve feet having been 
known. Its flesh is said to be almost uneatable, being hard, coarse, and ill 
flavoured, The HAMMER-HEADED SHARK produces living young, and from the 
i, 
