PACKARD.] ' TRANSFORMATION OF ARTEMIA. 493 
schibai Lake by rain, the furca becomes in the late generations longer 
and the number of bristles greater, since under these conditions the 
growth of Artemia salina is less retained and the sexual maturity ap- 
pears not so early, that is, not earlier than the complete development 
of the body-parts, which, however, is not so well defined in this species, 
being, as it were, but a relative matter. Also the termination of the 
upper antenne, being the most constant character of this species, modi- 
fies to a certain degree. For instance, I found in the autumn of one 
year, at low temperature and dilated salt water of the Chadschibai 
Lake, in many individuals of A. salina near the end of the upper an- 
tenne five olfactory bristles, instead ofthe normal number of four. In 
domesticated generations of this species in gradually diluted salt water 
we perceive also five olfactory bristles on the upper antenne. With 
the distinctive characters of A. salina we have also to include the form 
of the gill-sacs. They are in A. salina of an elongate form, their width 
being on the average twice less than their length. This character dis- 
tinguishes A. salina from A. milhausenii, in which the gill-saes are of 
oval or more rounded form, being on the average two-thirds as wide as 
long. 
As another important point of distinction of A. salina from the nearest 
allied races, [ mention the proportional size of the posterior part of the 
body constituting the apodous segments; the anterior part from the 
beginning of the head to the end of the last leg-bearing segment, i. ¢., 
to the beginning of the first apodous segment and the posterior part of 
the body, from the beginning of the first apodous segment to the end 
of the last seement before the beginning of the furca. The furca does 
not come into account, as its length is variable, being for instance in 
A. milhausenii, with which the other forms must relatively also be com- 
pared, entirely missing. We find that in A. salina the anterior part of 
the body is somewhat shorter than the posterior; proportionate to it 
as five to six oras five toseven. This relation of the parts also depends 
upon the concentration of the salt water in which these generations 
live. In reduced concentration the posterior part has an inferior size 
than in the higher concentration. Altogether the postabdomen of A. 
salina becomes longer and more slender with increased concentration. 
In many of our specimens with the character of A. milhausenit, which live 
at self-deposition of salt or nearly so, the anterior part of the body is 
twice shorter then the posterior part. 
To the most variable characters of A. salina we must reckon that 
reddish layer which lines the anterior part of the alimentary canal in 
the shape of a tube, which layer Joly' calls the liver, and Leydig? the 
stomach, as he separates it from the following part, the alimentary canal 
to the anal orifice. For better distinction I shall call the anterior part 
the stomach part of the tract, the second, the posterior part. The 
stomach part of the tract terminates in Artemia about in the middle of 
the seventh apodous segment, but the length of this part depends upon . 
the concentration of the salt water inhabited by the generations of this 
species, and partly also from the growth (age) of the specimens. At 
high salt eapacity of the water this part of the tract does not reach to 
the end of the sixth apodous segment of the abdomen; at lower salt 
1 “Sur ’Artemia salina” in Annales des Sciences nat. 1840, pp. 238 to 239. 
2¥. Leydig, ‘‘Ueber Artemia salina und Branchipus stagnalis,” Zeitschrift f. w. Z. 
1851, pp. 283 to 204. 
3 The first part of the tract Claus calls ‘‘ Magendarm,” the second part, the “ End- 
Darm” in his ‘‘Zur Kenntniss des Baues und der Entwicklung von Branchipus stag- 
nalis und Apus cancriformis,” 1. c., as above. 
