496 ‘GEOLOGICAL SURVEY OF THE TERRITORIES. 
Important for my purposes is the following remark of Dr. Nitsche 
concerning Branchipus Grubit (von Dybowski) from the neighborhood 
of Leipzig: ‘Further on it exhibited the remarkable circumstance that 
two races of this species occurred: a larger one about 20 to 22™™ long 
and a smaller one about 15™™long. These lived in various ditches, and 
those inhabited by the larger race contained far less specimens than 
those inhabited by the smaller race.”!. The existence of two races of 
different sizes of Branchipus Grubti and the circumstance that the 
specimens of these races lived in different ditches is of importance. It 
would be interesting to learn? whether this ‘‘ratio quantitatis” between 
two races occurs at any time of the year (which I do not accept). In- 
formation about this latter point would especially be of value, whether 
the specimens of these two races occurred together in one and the same 
ditch. 
Artemia salina Milne-Edw. varietas b., like variety a., in reference to 
the species, represents, so to speak, another branch of the middle radi- 
cal form, from which it, together with the normal species, originated in 
the distribution of generations i in a modified element; this second variety 
(var. b.) represents in its distribution in an element of lesser concen- 
tration of the salt water the progressively developed generations of the 
species itself. 
Variety b. occurs in salt ditches near Odessa and Sebastopolis. In 
salt ditches near Odessa I found it at a concentration of 4° Beaumé, 
while at the same time in the other salt ditches of higher concentration 
specimens of A. salina occurred. 
The length of the specimens of variety b. scarcely differs from the 
length of specimens of the normal species; its postabdomen, however, is 
shorter and stouter than in the species; the furca is by far longer and more 
bristled than in the normal species. The postabdomen (exclusive of the 
fureca) is in this race also a little shorter than the anterior part of the 
body, at least in the young, though sexually mature specimens, while 
the same somewhat elongates with age. As the posterior part of the 
body elongates with the gtowth of the specimens to mature and old 
age, and likewise in heightening the concentration of the salt water, we 
can presume that it is in A. salina var. b. either shorter than the ante- 
rior part, or equals it, or is scarcely longer than the same, while in the 
species A. salina the posterior part of the body is considerably longer 
than the anterior.2 Only in the young specimens of the species itself, 
some time before becoming sexually mature, the posterior part of the 
body is still shorter than the anterior. In any case, such a character 
cannot sharply demarcate this variety from thenormal species. There are 
other characters by which we can distinguish them. The furca of the 
variety b. does not show any simple conical protuberances at the end of 
the abdomen like two prolongations of the same, but real—even if not 
segmented from the end of the abdomen, but only by a transverse, 
easily noticed ring, separated at the sides from its base—divided furcal 
lobes. They are rather large and more developed than in other forms 
of Artemiz. They have the shape of. lancet-like plates, tapering 
1H. Nitsche: ‘‘Ueber die Geschlechtsorgane von Branchipus Grubii (von Dyb.).” 
Zeitschrift, f. w. Z., vol. xxv, p. 231. 
2 From Dr. Nitsche we cannot expect to hear all the singularities referred to the 
race of Branchipus Grubei. Especially inquiring into the structures of the sexual organs 
of Branch. Grubii, which formed the topic of his dissertation, Nitsche sufficiently 
pointed out the existence of two races of Br. Grubii, calling it a remarkable circum- 
stance. 
’The postabdomen is on the average longer and slenderer in the species of Aston 
than in those of Branchipus. 
<s 
