INFLUENCES AND EFFECTS. 221 



perused with advantage. Fish are subject to a mouldy-looking 

 parasite belonging to the Saprolegniei, and a similar form 

 attacks the ova of toads and frogs. Grold fish in globes and 

 aquaria are very subject to attack from this mouldy enemy, and 

 although we have seen them recover under a constant change of 

 water, this is by no means always the case, for in a few weeks 

 the parasite will usually prevail. 



The influence of fungi upon animals in countries other than 

 European is very little known, except in the case of the species 

 of Torrulia found on insects, and the diseases to which silk- 

 worms are subject. Instances have been recorded of the occur- 

 rence of fungoid mycelium for in most it is nothing more in 

 the tissues of animals, in the hard structure of bone and shell, 

 in the intestines, lungs, and other fleshy parts, and in various 

 organs of birds.* In some of the latter cases it has been de- 

 scribed as a Mucor, in most it is merely cells without sufficient 

 character for determination. It is by no means improbable that 

 fungi may be found in such situations ; the only question with 

 regard to them is whether they are not accidental, and not the 

 producers of unhealthy or diseased tissues, even when found in 

 proximity thereto. 



There is one phase of the influences of fungi on the lower 

 animals which must not be wholly passed over, and that is the 

 relation which they bear to some of the insect tribes in fur- 

 nishing them with food. It is especially the case with the 

 Coleoptcra that many species seem to be entirely dependent on 

 fungi for existence, since they are found in no other situations. 

 Beetle-hunters tell us that old Polyporei, and similar fungi of 

 a corky or woody nature, are always sought after for certain 

 species which they seek in vain elsewhere,f and those who pos- 

 sess herbaria know how destructive certain minute members of 

 the animal kingdom are to their choicest specimens, against 

 whose depredations even poison is sometimes unavailing. 



Some of the Uredines, as Trichobasis suaveolens and Coleospo- 

 rium sonchi, are generally accompanied by a little orange larva 



* Murie, in "Monthly Microscopical Journal" (1872), vii. p. 3 49. 



t See genus Mycetophayus, "Stephen's Manual Brit. Coleopt." p. 132. 



