ORDER PCECILOPODA. 369 



of a bistreous colour, which they contain, render these rami- 

 fications perceptible. The coecum 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. Miiller has described it in this state, 

 under the name of Argulus charon. 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 antenna?, 

 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. XIII. B b 



