TBANSMIGRATIONS AND METAMOEPHOSES. 185 



and are set at liberty in the stomach. The stomach of 

 of the carnivorous animal is a sieve through which thou- 

 sands of parasites are often introduced at each repast, 

 and fishes lodge many which often pass from one stomach 

 to another. Their whole life is spent in these migra- 

 tions; they are travellers who have their abode in railway 

 carriages, and never take their departure at the stations. 



Each stomach is, in fact, a station, very frequently 

 quite filled with merchandise, which disappears with the 

 station itself by the next train. Happy are those who 

 find themselves in a carriage safely on the rails towards 

 its destination. Many are called but few chosen. How 

 many journeys some of these travellers have to take 

 before they find their host ! 



It is often very interesting to open a fish which has 

 made a good meal ; its stomach and intestines contain, 

 first of all, the usual worms ; • the half-digested prey, in 

 its turn, encloses some ; and it is not rare to find besides 

 them the parasites of those which were swallowed to- 

 gether with their host. 



The animal is usually attacked in its youth by the 

 parasites which it harbours all its life. In order to know 

 the inhabitants of some fishes, we must examine them 

 shortly after they are hatched. 



In the criche the parasite occupies an organ which 

 is closed, and without communication with the outer 

 world ; it inhabits the garret of its first host ; in its last 

 host, which represents the maternity asylum, it dwells, on 

 the contrary, in the largest apartments, and never ceases 

 to be in direct communication with the exterior. Thus, 

 in the first animal, it is often completely immovable 

 and under a form which we have named scolex ; in the 



