88 Beport of the Billiarzia Mission in Egypt, 1915 



After leavinr; the mother-cyst, the dau<,'hter-sporocysts migrate 

 into the tissue of the hepatic gland and grow rapidly. They 

 become greatly elongated and eventually ramify throughout the 

 organ, so increasing its bulk that an infected mollusc can be 

 detected at a glance. The colour also of the organ is changed. 

 In Bullinus and Planorhis the gland is brown or dark green, but 

 when infected this changes to ochre. 



The ends of the daughter-sporocysts are solid, but the walls 

 of the tubular bodies are very delicate and transparent, so delicate 

 that it is impossible to dissect a complete sporocyst free from the 





Fig. 43.~Tenninal portion of a daughter-sporoe5'st containiiij:! fully developad 

 cercaria?. 



tissues. As the cercaricic develop within them, the sporocysts may 

 become markedly constricted by the host tissue (fig. 44), and a 

 certain amount of multiplication may possibly occur through scission. 

 These sporocysts appear to absorb their nutriment through their 

 walls, as they have neither oral sucker nor alimentary canal. The 

 glandular tissue of an infected organ disappears apparently through 

 pressure atrophy (fig. 44). The sporocysts are capable of travelling 

 by wriggling movements. The cercarioe leave the sporocysts through 

 simple rupture of the over-distended wall. They are discharged 

 from the mollusc in "puffs," a number being periodically shot into 



