50 
POPULAE SCIENCE EEVIEW. 
amongst them all, behold a creature of nobler mien and appear- 
ance moving stately along, a whale amongst the minnows ! It 
has no shell or carapace, but is quite uncovered. It is about an 
inch in length, is nearly transparent, but beautifully tinged in 
parts with red and blue. The feet appear to be rather nume- 
rous, are all leaf-like or foliaceous, and seem to be in constant 
motion. The creature, unlike most aquatic animals, swims on 
its back ; and as it gently glides along, its feet are waving to and 
fro with an undulatory motion, like as when the wind passes 
over a field of corn. This is the Fairy- Shrimp, the Gkiroce- 
phalus diaphanus * (figs. 1,2). 
This cc fairy-shrimp ” is of a slender, elongate form, and 
is remarkable on account of the shape and structure of the 
head. It has two kinds of antennae, one pair slender and 
thread-like, the other, the lower pair, like two horns. In the 
female they are comparatively small, but in the male are remark- 
ably large, the basal joint of a beautiful transparent bluish- 
green colour, the extremity tipped with a fine red hue (fig. 2). 
Attached to this are various organs which we have not space to 
describe, and which give it a remarkably complicated appearance. 
Unlike the generality of the Entomostraca, the fairy-shrimp has 
two large eyes, one on each side of the head, standing out upon 
projecting foot-stalks. The feet are eleven pairs in number, 
and serve the purpose of gills, for respiration. The body ter- 
minates in a tail composed of two fin-like divisions, which are 
finely feathered on the edges, and it is by this organ that pro- 
gressive motion is produced. Striking the water rapidly from 
right to left, it impels its body forwards, and darts away like a 
fish. It is certainly the most beautiful of all our native Ento- 
mostraca, and as it moves with graceful elegance through its liquid 
element, forms a sight which the most indifferent observer cannot 
see without pleasure. The female (fig. 1) has a large external 
bag of eggs, which, when the proper time arrives, opens at the 
point, and the ova are thrown out by a sudden jerk loose into 
the water. These eggs vary in number from 100 to 400 at each 
laying, and in about a fortnight they are hatched, and the young 
issue forth into the world. Like those of the cyclops, the young 
are very unlike the parent. At fig. 3, we have represented one 
soon after birth. This shows a little creature consisting of two 
nearly equal portions, head and body. In a short time we can 
observe it moult, or cast off its shell (fig.4) ; and if we watch care- 
fully, we may see this process repeated at short intervals, and 
can trace the gradual development of the larval animal till at 
last it appears in the state of the perfect insect. 
In the neighbourhood of London, there are many localities 
* Legion, Branchiopoda ; order, Thjllopoda ; family, Branchipodida. 
