BIOLOGICAL STUDY OF TAP WATER. 425 
METAZOA. 
The other animal forms which have been noticed are not very 
numerous. 
Vermes.—The worms are represented by the Vematoid Anguillula 
fluviatilis, which is not very common ; and by one or two species of 
Rotifera belonging to the family Brachionidae, in which there is a 
carapace and one or more eye-spots. These are Anuraea stipitata, 
and another species with the back of the carapace ornamented with 
facets, as well as furnished with teeth in front. A species of the 
genus Brachionus itself has also been observed. 
ArrHropopa.—The Crustacea are represented by at least two 
species, Cyclops quadricornus and Daphnia pulex, or a nearly allied 
form. Cyclops especially is common both in the adult and larval 
stages. 
Belonging to the Tardigrada I have noticed a species of Macrobi- 
otus rarely present, probably /. Hufelandi. 
Epithelial cells, bristles of crustacea and insects and other frag- 
ments are to be found among the debris which is always present in 
considerable quantity, and which is generally described as ‘ flocculent 
matter.” It consists mainly of broken Diatom frustules, as a good 
deal of it remains after boiling in nitric acid, partly also of decom- 
posed organic matter in a fine state of division, as well as a small 
quantity of mineral matter. 
The bearing which the foregoing observations have on the question 
of the purity of Toronto’s water supply may now be briefly alluded 
to. Judging from the miscroscopical examination of the suspended 
matter in the water, I would characterize it as one of the purest 
of natural waters. inasmuch as it is almost entirely free from any 
organisms which are either themselves directly injurious, or which, 
by their presence, would show that water containing them must 
necessarily be injurious. The great bulk of the sediment consists of 
vegetable matter, and that in a living condition. The animal forms 
are chiefly Flagellate Infusoria, which are inhabitants of fresh water, 
not depending for their food on dead, decaying, and poisonous 
matter. 
The absolute amount of sediment in the water I cannot accurately 
state; but the chemical analyses show the amount of albuminoid 
ammonia to be very small (averaging ‘003—-007 grains per gal.) ; 
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