58 
BRITISH ENTOMOSTRACA. 
opening at its lower extremity to allow the ova to escape. 
The digestive tube commences a little above the man- 
dibles, and is preceded by a pharynx, consisting of two 
vesicles, which appear divided into cells, and present the 
appearance of convolutions similar to those of the brain of 
the superior animals. 
The heart or dorsal vessel is exactly like what is seen 
in the Chirocephalus. 
The Artemiae are found exclusively in salt water, and 
though they do occur in salt marshes, still they are to be 
found in greatest abundance in water that is very highly 
charged with salt. “ Myriads of these animalculi,” says Mr. 
Rackett, “ are to be found in the salterns at Lymington, 
in the open tanks or reservoirs where the brine is deposited 
previous to the boiling. It attains the desired strength 
by evaporation, from exposure to the sun and air, in about 
a fortnight. A pint contains about a quarter of a pound 
of salt, and this concentrated solution instantly destroys 
most other marine animals / 5 In these reservoirs there is 
always a certain quantity of this strong brine allowed to 
remain, and there these little creatures are found in greatest 
abundance and in greatest enjoyment ; whilst in what are 
called the sun-pans, where the brine is made by the ad- 
mission of sea-water during the summer, and which are 
emptied every fortnight, they are never found at all. 
During the fine days in summer they may be observed in 
immense numbers near the surface of the water, and as 
they are frequently of a lively red colour, the water ap- 
pears to be tinged with the same hue.* “ There is nothing 
more elegant , 55 says M. Joly, “than the form of this little 
Crustacean ; nothing more graceful than its movements. 
* The fact that salt water, when highly concentrated, frequently assumes a 
red colour, has been often attributed to the presence of great numbers of the 
Artemia salina. Indeed the cause of this red colour, which was well known 
to take place in the salt marshes and reservoirs of salt water at Montpellier, 
was made, some years ago, the subject of very great discussion in France, 
before the Institute. M. Payen first maintained the cause to be the pre- 
sence of Artemiae; M. Duval, however, declared that it arose from micro- 
scopic vegetables, species of Haematococcus and Protococcus. After a keen 
