508 GEOLOGICAL SURVEY OF THE TERRITORIES. 
taken for articulations. Furthermore, according to Rathke, this species 
has, besides the upper lip, no other oral parts, while S. Fischer,! in com- 
pleting the description of this species, describes beside the upper lips, 
also other oral parts (upper and lower jaws), which differ in nothing from 
the same parts in other Artemia. In our specimens with the characters 
of A. milhausenv, these paris fully correspond with the description given 
by 8S. Fischer. Such a great contradiction between the authors awakes 
a doubt whether they had todo with the same forms, thus rendering the 
determination of this species difficult. Likewise Rathke does not men- 
tion in this species the existence of the posterior branchial lobes, while | 
he dwells at length upon the gill-sacs, as if the former were not existing 
at all. Butin reality Rathke probably did not see them at all on account 
of their transparency. These branchial lobes exist in our specimens 
(and those from the Krimea) with the characters of Artemia milhausenti, 
and 8. Fischer gives anillustration of them with his description of Artemia 
kdppeniana. On the coutrary, in Rathke’s description there is yet a dif- 
ference in the length of the abdomen. In our individuals with the char- 
acters of Artemia milhausenvi, the posterior part of the body, consisting 
ot apodous segments, is longer than the whole anterior part, being to it 
in proportion at least as eight to five; butin the specimen described by 
Rathke the posterior part of the body is shorter than the anterior. 
However, we can with certainty say of Rathke’s description, what length 
the posterior part of the body had in the specimens described by him. 
From his words it is to be assumed that Rathke calls the whole posterior 
part of these animals (without the first two apodous segments of the abdo- 
men?) a tail. The comparative length of this tail he compares with the 
tail (postabdomen) of the scorpions, and shows by the illustration that 
the posterior part of the body is nearly + shorter than the an‘erior part, 
while in the stated measurements he has such figures aS surprise me 
by their disproportion, and according to which the tail would be two 
and a half times shorter than the anterior part of the body. The 
latter can only be called a misprint; it remains unknown, however, 
how the omission of oral parts (excepting the upper lips) and the 
posterior branchial lobes can be explained in Rathke’s descriptions. * 
If the degradation of this form had proceeded so far, that with them 
these parts were not developed at all, it would have been different from 
the form examined and more completely described by 8S. Fischer. S. 
Fischer, however, calls the tail of the form examined by him, long, which 
expression! H. Rathke does not use, but the termination of the post- 
abdomen, according to Fischer’s drawings, differs from the termination 
of this part in Rathke’s drawing, not showing any broadening. It is 
possible that Rathke and Fischer had different forms in possession, 
whereby Rathke’s form is identical with the very degraded generations 
of Artemia salina, or corresponds with them, while Fischer’s form is a 
degraded form of the larger variety a. of Artemia salina. 
Finally, on the other hand, Grube’s? diagnosis of this species aiifers 
from our generations with the characters of Artemia milhausenti, in 
having on the terminal lobe (lobus tarsalis Grb.) not about 17, but about 
25, marginal bristles; it is possible that here Grube borrowed the num- 
ber of bristles from Rathke’s drawing, who drew on his small illustra- 
tion about such a number of bristles, only saying in the description 
1Milne-Edwards calls in his diagnosis the postabdomen of Artemia milhausenti also 
long, but does not take this expression in his diagnosis of Artemia salina. 
2“ Bemerkungen tiber die Phyllopoden” in Archiv fiir Naturgesch. 1853, p. 145. 
He correctly remarks, amongst other things, that Rathke could not have observed 
the very tender and transparent posterior branchial lobes in so old alcoholic specimens. 
