THE LIVING WORLD. 
65 
identical with those in the leech. Unlike fishes, the lamprey is not provided 
with gills, the breathing being accomplished through seven orifices on each 
side, that are distinct and on a line with the eyes. Water is drawn in through 
these and thrown out again by each respiration. They are also peculiar in 
producing their young after development in the ovary, passing out through a 
genital pore, and then undergoing a metamorphosis somewhat like the frog, 
the larvae having at one time been regarded as a distinct genus. 
Though the lamprey is 
viviparous, it constructs nests, 
the object of which is not 
clearly understood. When the 
breeding season arrives they 
proceed up towards the source 
NEST OP THE WHITE-FISH. 
NEST OF THE SUN-Eibti. 
of a stream, sometimes in vast shoals, and at selected spots begin the construc¬ 
tion of nests, probably in which to harbor the young while in the larval state. 
In forming these the male and female unite their labors, and seizing stones 
by means of their suctorial mouths, convey them to the place desired. Often 
the sexes will be seen attached to a larger stone than one alone would be 
able to move, but by joining forces they make their success certain in trans- 
5 
