162 Life and Immortality. 
the rearing of their submarine castles are ordinarily sub- 
jected to a swift current, the largest stones, which it would 
be thought impossible for them to move, are looked for up 
stream. A suitable one found, and a favorable position pre- 
sented, the sucking mouth is fastened to it, and by a con- 
vulsive effort, the tail of the fish being raised aloft, the heavy 
stone is lifted from its place, the current pushing against the 
fish and stone, bearing them along several feet before they 
sink. Another effort of the fish, and the rock is again raised 
and carried down stream, until finally, by repeated liftings 
and struggles, the ingenious, persevering nest-builder is swept 
down to the nest, where the load is deposited. This labo- 
rious work is carried on until the pile has attained a height 
of two or three feet, and a diameter of four. No special form 
seems to be necessary. The nest is generally oval, compact 
and well devised to contain the eggs, which are carefully 
deposited within, thus affording protection in its numerous 
interstices for the young when they hatch. When about six 
inches long, the young Petromyzon marinus, which is a strange 
little fellow, is devoid of teeth, and blind, and possesses so 
many characteristics distinct from the parent, that for a long 
time he was considered a separate species, and even assigned 
a place in a different genus. Enormous nests are sometimes 
built. “John M. Batchelder, Esq., describes one, which he 
saw in the Saco River, Maine, that was about fifteen feet 
long, and from one to three feet in height, its position and 
triangular shape in vertical section being well adapted for 
securing a change of water, and a hiding-place for the young. 
The operation of building was very methodical, a hundred 
and more Eels being at work upon the structure. Water- 
worn stones, chips of granites and fragments of bricks, some- 
times weighing as much as two pounds and transported bya 
single individual, were utilized in the building. 
More remarkable, however, than any previously described, 
are the nests of the Fresh-water Chub, Sesotilus bullaris, 
which is known in some localities as the Stone Toter. 
