Their Collection and Investujation. ol 



imassistecl eye, but had a diameter or total length of as much 

 as from the one -tenth to the half of an inch. The inhabitants 

 of these relatively large tree-like or sac- shaped fabrications 

 in no case yielded a greater measurement than the 1 -4000th 

 or the l-3000th part of an English inch, so that the number 

 included in the larger aggregates is almost beyond calculation. 



The student must by no means confine himself to the 

 collection and examination of water-plants in his search for 

 Infusoria. Innumerable forms are to be met with growing 

 upon other aquatic animals : insect larvae, molluscs, and the 

 more minute Crustacea, yielding an abundance of different 

 forms, their "fluffy" appearance, as seen with the naked 

 eye or with the aid of a lens, being a sure sign of the presence 

 of the required organisms. The little Entomostracan — 

 Cyclops — may be more especially mentioned as commonly 

 supporting on its body and limbs a perfect forest-like growth 

 of infusorial types, including, it may be, representatives of 

 each of the three primary sections referred to in my earlier 

 observations. In this manner the class Ciliata is usually 

 typified by one or more species of Epistylis ; that of the 

 Flagellata by Cephalothamnium and Deltomonas ; while that of 

 the Tentaculifera may be represented by one or two species 

 of Podophrya ; and all of which Infusoria, as so far known, 

 are obtained under no other conditions. 



Although ponds, ditches and other expansions of water 

 may be recommended to the student as his first area of 

 exploration, these represent but one out of numberless 

 sources from whence Infusoria are to be derived. A multitude 

 of species are essentially parasitic, living within the intestinal 

 viscera of higher animals. Many terrestrial insects, worms, 

 and molluscs, discharge the duty of hosts to special varieties. 

 The frog, in common with other Amphibia, supports quite an 

 abundant infusorial fauna, consisting of both ciliate and 

 flagellate types ; while even the higher Vertebrata, including 

 horses, sheep, oxen, and man himself, are not exempt from 

 infusorial dependents.^ 



2 [An article descriptive of the chief varieties of parasitic Infusoria has 

 been contributed by the author to the ' Popular Science Review ' for 1880, 

 p. 293.— Ed. 



