•496 GEOLOGICAL SURVEY OF THE TERRITORIES. 



Important for my purposes is the following remark of Dr. Nitsclie 

 concerning BrancMpus Gruhii (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 IS'"'" 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 Branchijjus Gruhii and the circumstance that the 

 specimens of these races lived in different ditches is of importance. It 

 would be interesting to learn 2 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 6., like variety «., 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 in a modified element; this second variety 

 (var. h.) rei)resents in its distribution in an element of lesser concen- 

 tration of the salt water the progressively developed generations of the 

 species itself. 



Yariety b. occurs in salt ditches near Odessa and Sebastopolis. In 

 salt ditches near Odessa I found it at a concentration of 4P Beaum6, 

 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 h. scarcely differs from the 

 length of specimens of the normal species ; its postabdomen, however, is 

 shorter and stouter than in the species ; the f urea is by far longer and more 

 bristled than in the normal species. The postabdomen (exclusive of the 

 furca) 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 i)osterior part of the 

 body elongates with the growth 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. h. 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.^ 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 the normal 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 Artemise. They have the shape of lancet-like x^lates, tapering 



ipl. Nitsclie: "Ueber die Geschleclitsorgaiie von BrancMpus Grubii (von Dyb.)." 

 Zeitsclirifr, f. w. Z., vol. xxv, p. 281. 



^From Dr. Nitsche we cannot expect to hear all the singularities referred to the 

 race of Bravchipus 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. 



■*Tbe postabdomen is on the average longer and slenderer in the species of Artemia 

 than in those of Jirauchipus. 



