ORDER PCECILOPODA. 
369 
of a bistreous colour, which they contain, render these rami- 
fications perceptible. The ccecum is provided, towards its 
origin, with two vermiform appendages. 
The males are very ardent in love, which causes them to 
mistake one sex for another, or address themselves to females 
pregnant or dead. In coupling, they are placed upon the back 
of the females, to which they hook themselves by means of 
their cupper-feet, and remain in that situation for several 
hours. The length of gestation is from thirteen to nineteen 
days. The eggs are smooth, oval, and of the whiteness of 
milk : they are fixed with a sort of gluten on stones, or other 
hard bodies, either in a right line, or in two ranks, to the num- 
ber of from one to four hundred. When pressed against 
each other, their form becomes almost hexagonal. 
Twenty-five days after the laying, and after having at first 
assumed a yellowish and opake tint, we commence to distin- 
guish the eyes and some portion of the embryo. Subsequently, 
at the end of about ten days, or towards the thirty-fifth day 
after the laying, the shell is cleft longitudinally, and the young, 
or tadpole, comes into the world. It is then scarcely three- 
eighths of a line in length. Its form generally resembles what 
it is to be in the adult state ; but its locomotive organs present 
some essential differences. Midler has described it in this state, 
under the name of Argulus chevron. Four oars, or long arms, 
two of which are placed before the eyes, and the other two be- 
hind, terminated, each, by a pencil of flexible and pinnated 
setae, which the animal moves simultaneously, and by means of 
which it swims with facility and by jumps, issue from the 
anterior extremity of the testa ; they do not represent antennae, 
as these last organs are also to be seen. The cupper- feet are 
replaced by two strong feet, elbowed near their extremity, and 
terminated by a powerful hook, with which this animal can 
fasten on fishes. Other feet, proper to the adult state, viz. 
those of the second and third pair, or the two ambulatory and 
VOL. X ITI. B b 
