9134 Fishes. 
* When put into a vessel of water (no easy matter without injuring 
it, as it adheres so firmly to its hold), it immediately clings to the side 
of its new habitation or to the first solid substance with which it comes 
into contact. Here it will probably remain for a considerable time 
unmoved, or now and then shift its position a few inches, or take a 
wayward start, and wriggle along with an awkward sort of agility to 
some other part of the aquarium, to which it sticks fast in a moment, 
as before. During the night it is much more restless, but, so far as I 
am aware, it has no power of hovering in the water, or swimming 
deliberately to and fro, as other fishes do, its locomotive powers consist- 
ing only of the ability to shift from one stationary position to another, 
“As it thus has no power of pursuing prey I conjecture that its 
subsistence is derived from those microscopic organisms which are 
scattered abundantly through the water, and which furnish support to 
multitudes of other creatures more strictly immoveable. In the case 
of these, which are for the most part invertebrate, strongly ciliated 
surfaces are provided, which produce constant and forcible currents, 
and thus the floating atoms in the surrounding fluid are carried along 
to the orifice of the digestive canal. Our little sucking fish has no 
external apparatus of cilia that I am cognisant of, but a similar effect 
is produced in another way. I have noticed that while this little fish 
remains stationary, being fast moored by its breast anchor, it maintains 
a constant and regular fanning with its filmy pectoral fins. This habit 
seemed to me at first useless and unaccountable, but, on consideration, 
I have little doubt that its purpose is to produce a more free and rapid 
change of the surrounding water, and that it is one of those compen- 
satory actions that we frequently meet with in physiology, and that 
are so interesting.” 
It is worthy of notice that each of my pets usually retained his own 
particular shell, and if he occasionally took a gliding turn round the 
sides of the aquarium, he generally came back to his old home. But 
their rambles were of unfrequent occurrence, and their locomotion 
evidently a matter of labour. The reason of this is patent: the Lepi- 
dogaster bimaculatus has no swimming bladder, consequently he swims 
about, with apparent difficulty, by means of his fins and tail. When 
tired or disposed to return to his habitation, he ceases all motion, and 
drops to the bottom by his own specific gravity. I have said that my 
favourites soon became domiciliated. I think that at the end ofa 
fortnight they knew me so well that they would follow me with their 
beautiful little eyes to whichever side of the aquarium I happened 
to stand, and sometimes they would leave their shells aud come over 
a 
