PACKARD.] TRANSFORMATION OF ARTEMIA. 489 
air) of the salt water. By changing the air-capacity of the salt water 
by a changed concentration of the water, we can at least explain a num- 
ber of interesting phenomena in the life of Artemia. 
1. If we in certain limits dilute the salt water too much in domesti- 
cating Artemia, then the animals become, by the too much reduced con- 
centration of the salt water, transparent, attenuated, their intestinal canal 
empties and becomes translucent, the gill-sacs often blacken, and the 
animals will die at the bottom of the jar, as it were, of debility. Butif 
we in time notice at the excessive dilution of the salt water the sickness 
of the animals, and if we, instead of augmenting the concentration of 
the salt water, heighten its temperature a few degrees, the diseased 
animals will become animated, the intestinal canal fills itself, the mo- 
tions become more rapid, the animals leave the bottom of the jar, doing 
well in such diluted salt water at a corresponding higher temperature. 
It seems tome that such a temperature supplants the superfluous air of the 
diluted salt water, which in the organism of the animals produced a too 
great oxidation, leading to weakness, during which the nutritive sub- 
stances could not replace the consumption. If by too strongly diluting 
the salt water the Artemia is consumptive, on account of want of nour- 
ishment, owing to the dying off of those microscopic organisms on which 
Artemia lives, these animals would not have revived so soon after a cor- 
responding increase of temperature. Moreover, microscopic organisms 
appear in the diluted salt water in great number, even Infusoria, while 
Joly! observed that Artemiz are omnivorous, and that they principally 
live on the lowest organisms of the vegetable kingdom peculiar to the 
salt lakes, such as various forms of Chlamidomonas, zoospores of Clado- 
phora, &c. 
2. If we, in domesticating Artemia, excessively increase the concentra- 
tion of the salt water and not sufficiently gradually, its alimentary canal 
becomes solidly constipated, the animals keep nearer the surface of the 
water and die there, especially during exuviation, which is hereby just 
as difficult to overcome as in too much diluted salt water. However, if 
we in time in this case lower the temperature, instead of diluting the 
salt water, the animals, even at a too high concentration of the salt 
water, revive, doing well in such a water with, to a certain degree, low- 
ered temperature. It seems to me that in this case such a combination 
of high concentration and temperature is formed. bearing to the equi- 
librium of aération in the water, i. e., the quantity of air in the salt water 
is lessened by the increase of its concentration for just so much, as it is, 
according to physical laws, heightened by lowering the temperature. A - 
want of nourishment in very saline water is here out of question, since 
such a water is inhabited by immense numbers of simple organisms, 
and even at a concentration, allowing self-deposit of salt, great quanti- 
ties of a red Monad occur, whichis known under the name of Monas 
dunalit Joly (Diselmis dunalii Dujardin=Chlamidomonas dunalit Raben- 
horst). 
3. If we gather out of a salt lake the adult Artemizx, together with 
their larve, and dilute the salt water to excess, then the larve will soon 
expire, while the adult individuals long after resist the dilution of the 
salt water. It appears that the larve of Artemia die faster in too 
strongly diluted salt water, because the small stock of material in the 
organism is not sufficient toward the intense oxydation in consequence 
of an excess of oxygen in such a water. 
4, In a broad jar and at alow surface of water these animals also 
1Joly, Sur ’Artemia salina, Annales des sciences naturelles, vol. xiii, Zoologie, pp. 
246 and 255. 
