14 
micaceous appearance, and cause it to split into thin lamine like 
schistose rocks. 
Lyell mentions that analogous deposits on the grandest scale 
are forming in the great Canadian lakes, as in lakes Superior and 
Huron, where beds of sand and clay are seen enclosing shells of . 
existing species. 
The living Cypris of our own time is a very active creature, 
and his erratic movements render him a more difficult object to 
study than the rooted Zoophytes. Although very minute they are 
readily discerned by the unassisted eye, and especially those which 
proceed by a series of quick jerks, and have on this account been 
called water fleas. The little animal resides between two valves 
or shells of a calcareous brittle material and might readily be 
mistaken for a small mollusc. The shells are united at the back 
by a ligament and muscles, by means of which the creature can 
open or shut them according to its requirements. 
It has a single eye and two pairs of antenne, the ends of 
which in some species are decorated with plumes, and are by some 
observers supposed to act as respiratory organs, as well as to assist 
it in swimming. There is, however, much discrepancy amongst 
authors as to the number of feet, some stating that there are only 
four, but this would present us with the singularity of an ‘ insect 
quadruped,” which, to borrow the phraseology of our old friend 
Euclid, would be absurd, therefore for the sake of uniformity we 
had better regard it as possessed of one pair of antenne and six 
legs, which it uses with great activity in running over water weeds 
and other objects. It has a double tail furnished with hooks and 
long claws, which it can protrude, telescope fashion, from its body. 
This organ appears to be used in cleaning the interior of its shells. 
It lays about 20 eggs at a time, attaching them to parts of water 
weeds, several individuals repairing to the same place for this 
purpose. According to Dr. Baird they are hatched in about four 
days, the young making its appearance as an almost perfect animal 
but undergoing several moults. This process of exuviation takes 
place with the adult after each laying, and is most wonderfully 
complete, for not only are the outer shells thrown off but the most 
minute coverings of the antenne. Strauss says the food of these 
small creatures consists of a mixed diet of animal and vegetable 
substances. Individuals of one species have been seen to devour 
eagerly the dead of a species different from themselves. As it 
.seems a law of nature that living things should either eat or be 
eaten, the various species of Cypris are swallowed in large quanti- - 
ties by fish, the flavour of which is supposed to be due to some 
extent to this kindof food. They are also freqnently found in the 
vesicles of the ultricularia or bladder-weed, so that it would appear 
they sometimes fall victims to this carnivorous water-weed. When 
the ponds dry up in the summer the Cyprides preserve their lives 
