ARGULUS. 253 



the little intruder, and that however eager after food they 

 might 1)6, they would never willingly touch an Argulus ; 

 and that if by chance a fish .should swallow one, it would 

 almost immediately afterwards be rejected. 



The males are always considerably smaller than the 

 females ; and appear, especially in summer, very ardent in 

 pursuit of them. They course up and down over the whole 

 surface of the fish in search of a mate, and should they 

 not succeed in meeting any, they leave their habitation, 

 and go elsewhere seeking for one. When they succeed, 

 the male mounts upon the female's back, and carrying his 

 body laterally he crosses that of the female, embracing her 

 at the same time wdth his natatory feet. This copulation 

 frequently endures for several hours, and during that 

 time they adhere so closely, that they cannot be separated 

 without considerable difficulty. In the unimpregnated 

 female the matrix is very small ; but soon after fecunda- 

 tion it begins to increase in size, and in a short time it 

 occupies almost the wdiole cavity of the thorax. The 

 number of eggs is very considerable, in the Argidas folia- 

 cens amounting sometimes to 400 ; in the Argulus Cafo- 

 stomi upwards of 1500 have been seen deposited b}^ one 

 female. They carry their eggs for a period between thir- 

 teen and nineteen days ; and then, when the female is 

 ready to spawn, she detaches herself from the fish, upon 

 which she has been living, and seeks a suitable place to 

 deposit them. This is either upon a stone or some solid 

 body, and as she lays them, she glues them together, so 

 that they might be all taken up in a mass. They are laid 

 side by side in rows, and are at first of an oval form and 

 of a white colour. They soon after become of a dirty 

 yellow, and thirty -five days after being laid, the young are 

 hatched. In form they resemble a good deal the adult, 

 but differ considerably in construction and development 

 of their organs. Deceived by this, Miiller forms of the 

 imperfect young a distinct species, — an error wdiich Jurine 

 has pointed out. The shape is oval, or somewhat pyri- 

 form, and the eyes and siphon are perfectly formed. 



