494 GEOLOGICAL SURVEY OF THE TERRITORIES. 
capacity of the water, but especially in autumn, it exceeds by far the 
beginning of the eighth abdominal segment. Likewise this part is 
longer in old individuals than in young, otherwise sexually mature speci- — 
mens. If we examine, relative to this, specimens on the extreme concen- 
tration-limits of the salt water, we find a great difference amongst them. 
In A. milhausenii the stomach part of the tract scarcely reaches to the 
beginning of the sixth apodous segment, but in our species of Branchi- 
pus this part terminates not far from the anal orifice. 
Finally, we must mention as a character of our A. salina the following: 
The claspers, or the lower antennez in the males, are much broadened 
on their second joint, having such a form as the male claspers of A. ari- 
etina, according to a drawing of 8S. Fischer.! 
On the anterior part of the male claspers, between the head and the 
protuberances, serving to clasp the female with, near the bent-down 
margin, there are two groups of ten-pin-shaped teeth or spines, in one 
group on each side. It appears that these denticulate groups corre- 
spond as rudiments of the well-known appendages, occurring on the 
claspers of many species of Branchipus, as for instance in Branchipus 
spinosus. Such bundles of teeth or spines occur also in that form of 
Artemia examined by Ulianin from Sebastopolis, and which was re- 
garded by him asa race of Branchipus arietinus Grube (= variety of 
Avt. artetina Fischer). 
Artemia salina Milne-Edw. varietas a.—This form, called by me Arte- 
mia salina var. a., approaches the species Artemia salina so much that, 
beside its larger size, no other distinct characters exist by which we, with 
the general variability of so many characteristic points of the Artemiz 
of this species, could distinguish ‘the same. However, if we have speci- 
mens before our eyes of this or that form, we must confess that we have 
to do with forms differing so much that we even could regard them as 
different species of the genus Artemia. 
A view of profound truth has been expressed already in 1871, by 
Professor C. Th. von Siebold, on the comparison of descriptions of "Ar- 
temia salina ot various authors. Siebold says:? ‘“¢*In comparing the vari- 
ous descriptions and illustrations given of Artemia salina, we become 
convinced that probably with this species-name entirely different species 
or races were marked out, and therefore a revision of the species of the 
genus Artemia by carcinologists would be recommendable, though this, 
however, would necessitate a comparison of vast material, especially as 
the hitherto insufficient diagnoses of the species of Artemiz, without 
reference to the characteristic formation of the male heads, have been 
_ compiled.” Further on Professor Siebold, in perusing the descriptions 
of the second antenne of the males in Artemia salina and that of the 
postabdomen of this species, foresaw what is now actually corrobo- 
rated. I find two principal races of Artemia salina, one of which is of 
smaller size, the Artemia salina, but the other is Artemia salina varietas 
_a., and there are, besides, still other changes of its generations depend- 
ing on various concentrations of the salt water, including also those 
degraded and modified generations of the two races of Artemia salina, 
which are, as I suppose, recorded in zoological literature under the name 
of the species of Artemia milhausenii. 
The main distinctions of the variety a. of the species Art. salina 
forms another mean length of it. Accepting as the mean length of 
Artemia salina six lines, we must accept eight lines of French foot for 
1Middendorf’s sibirische Reise. St. Petersburg, 1851, Vol. II, Ist part. Table VII, 
fig. 32. 
2“ Beitrige zur Parthenogenesis der Arthropoden.” Leipzig, 1871, p. 203. 
