274 



THE DISEASES AND DISORDERS OF THE OX. 



have in virtue of the possession of a little flagellum or elongated 

 whip-shaped filament at each end. The zoospores or spores 

 finally escape from their enclosing sac or sporangium, and, 

 attaching themselves to the skin of the creature they infest, they 

 repeat the process of penetration. 



In the accompanying figure the sporangium A is seen filled 



Fig. 34. — Sapkolegnia of Salmon Disease. 



A Sporangium filled -vvitli zoospores, and in connection with them several young 

 mycelial threads. 



with oval zoospores, C ; several young filaments, B, are seen in 

 connection with some of the spores. Besides this method 

 of development, the parasite also reproduces itself in another 

 way, such for example as we may see in the Achlya, which forms 

 a mould around dead or weak flies and " blue-bottles," ivyberries, 

 &c. At the end of a filament a cell forms a large round sphere, 



