TRANSMIGRATIONS AND METAMORPHOSES. 



25a 



Echinorhijnchiis cjigas. Pigs disseminate the eggs, and the 

 embryos infest these larvae, in the bodies of which they 

 pass through then- principal changes. 



The Gregarinee are microscopic beings, with an 

 extremely simple organization, the natm-e and the 

 genealogy of which have only lately been known. They 

 live at first encysted by thousands together, under the 

 name of Psorospermide ; they are afterwards hatched in 

 the form of Amoeba, and then transformed into Gregarinae. 

 They migrate from one animal to another, or from one 

 organ to another, to settle in the intestine, where they 

 assume their adult form. In this state they are mono- 

 cellular, and do not at anytime possess organs which 

 resemble the sexual organs of other classes. The disease 

 of silk worms, known by the name of " pebrine," has 

 been attributed to the development of psorospermiEe. 



We give the representation (Fig. 74) of gregarinae 

 which we have fomid abundantly on the Nemertes ; and 



Fiir 74.— Grc^arinte of Xemertes F\g.75.-St!/lorhy7ichiis oligacanthus, from the 

 Gesseriensis. larva of the Agnon. 



(Fig. 75) a pecuHar species which lives in the larva of an 



agnon. 



