228 



SIPHON OSTOMATA. 



parasitic. They are met with adherent to the skins 

 and eyes of fishes, or sometimes to their gills and 

 the interior of their mouths. Their forms are ex- 

 tremely variable, and all appear to undergo several 

 transformations in their progress from birth to ma- 

 turity ; this group embraces 



The Pycnogons,* strange-looking creatures, of small size, with 

 very long limbs, and their body divided into segments. They mostly 



FIG. 174. PYCXOGOX, 



take up their abode under stones along the coast, or are found 

 crawling upon seaweed, or sometimes they hook themselves on to 

 fishes and other marine animals. 



The Fish Lice, among which may be mentioned the Caligus 

 Mutter i, found adhering to the gill-covers of the cod-fish, to which it 

 holds on by claws that terminate its fore-limbs, while with its beak 

 it sucks the food upon which it lives. A 11 of these 

 animals are parasitic, and are found attached to 

 the gills or other parts of fishes by means of a 

 formidable apparatus of hooks and suckers ; some 

 species seem permanently fixed to their victims, 

 but others are able to relax their hold at will and 

 change then* place. 



The Lerneans constitute a very extensive group, 

 remarkable for the singularity of their appearance. 

 When young they resemble the young of cyclops, 

 and are then provided with a frontal eye and 

 natatory limbs, swimming with facility ; but having 

 undergone a certain number of moults, they cease 

 to lead an erratic life. The limbs now, no longer 

 needed, become lost or waste away. The eye 

 generally disappears and the body assumes a 

 strange form. The female is at this time found 

 fixed to some fish or other aquatic animal by 

 means of curious appendages resembling distorted 

 limbs or moveable claws. As an example, we men- 

 FIG. 175. - LKRNBAN. tion the LernsBa monilaris, which attaches itself to 



* TTVKV&S, pycnos, thidc ; 701/1;, gony, the knee. 



