MARINE PHYCOMYCETES 



463 



and escape from the apex of a thick exit-tube-like hypha. During 

 transformation of the spore into a globular thallus nuclear division 

 is accompanied by an increase in the volume of the thallus. 



An earlier account by Neresheimer and Clodi (1914) deals com- 

 prehensively with the morphology, life history, and pathogenicity 

 of Ichthy ophonus hoferi. The later study by Fish (1934) em- 



Fig. 77. Schematic life cycle of Icthyophomts hoferi, which parasitizes 



fishes. (Adapted from Daniel.) 



ploys the name Ichthy osporidhnn hoferi for the pathogen, which 

 Fish encountered in sea herring, ale wife (Pomobohis pseudo- 

 harengus), and flounder (Pseudoplenronectes americanus) 

 throughout the Gulf of jMaine. He concluded that fishes become 

 infected by way of the alimentary canal. Association of these 

 species and cannibalistic food habits, especially of flounder, which 

 eats herring, account for acquisition of the pathogen. 



Several saprolegniaceous parasites of marine animals have been 

 observed. Apstein (1910) noted that Synchaeta monopus, a roti- 

 fer occurring in brackish waters along the Baltic Sea, may be in- 

 vaded by mycelia of an organism that he named Synchaetophagns 

 balticus. The hvphae may more or less completely occupy the 

 body cavity, destroying the organs and leaving only the outer 



