1g00-1901.] Report of the Microscopical Section. 227 
few short setze ; while the inferior antenne, which spring from 
the sides of the head, are large and much branched, each branch 
being finely plumose. 
The Daphnia belongs to the class of what are called Mon- 
oculi, or one-eyed animals. The eye is compound, consist- 
ing of about twenty separate crystalline lenses, and has a 
slightly rotatory motion, actuated by two sets of powerful 
muscles. This motion is very well seen if the animal is 
examined by a low power of the microscope in a live-box. 
In this position, owing to the transparency of the shell, 
the motions of the branchial plates can also be well seen. 
In female Daphnia the ovaries are, according to Baird, 
situated along the sides of the abdomen; and, in moderately 
young individuals, their position may be made out by the 
small, round, pellucid globules they contain. At the back of 
the shell, and behind the ovaries, is the brood-pouch into 
which the eggs are discharged from the ovaries, and where 
the young Daphnia may be observed in different stages of 
_ development. These eggs are sometimes spoken of as summer 
- eggs, and a considerable number of them may occasionally be 
_ found in the brood-pouch at one time. But eggs of another 
_ kind, called ephippial eggs,—also known as winter eggs and 
as resting eggs,—may mde certain conditions be produced. 
- The number of ephippial eggs produced by Daphnia is usually 
two. They appear, when aes developed, as dark-brownish 
objects at the back of the shell. The part of the shell in 
_ which these eggs are enclosed becomes thickened, and is by- 
_ and-by thrown off with the enclosed eggs, floating or sinking 
amongst the mud till conditions favourable for the develop- 
ment of the eggs occur. 
Cypris.—The Cypris is one of the genera into which the 
family of the Cypride is divided. It belongs to the order 
_ Ostracoda, of the legion Lophyropoda. The species studied 
was the Cypris tristriata, Baird, now Cypris virens (Jurine). 
It is one of the Monoculi, or one-eyed animals. The eye is 
not compound—that is, there are no traces of separate 
-erystallines. 
__. The whole body of the Cypris is enclosed in an oval shell 
like that of a small mussel, the two halves of which are 
attached to each other by a strong ligament which acts like a 
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