498 GEOLOGICAL SURVEY OF THE TEERITORIES. 



abdomen, the development of groups of spines from the above-men- 

 tioned groups of cuticular cells. However, these cuticular cells also 

 commence in free nature in fall generations of the species A. salina to 

 point themselves on their tips and to elevate themselves above the in- 

 tegument. To be sure under such external conditions the enlargment 

 of the furca and the number of their bristles testify in these specimens 

 to a lesser retention of growth than in summer at higher salt capacity 

 of the water and at higher temperature. These cuticular groups 

 of cells, or, in known cases, these denticular groups of spines occur- 

 ring near the base of the sensory bristle on the abdomen of A. salina 

 and its varieties, ai-e homologous with the minute denticular spines 

 occurring near the base of the sensory bristles on the lateral sur- 

 face of the postabdomen in both sexes of Branchipus ferox and B. 

 Sjjinosus. Concerning the large spines on the ventral surface of many 

 apodous segments (from the third to the eighth) of the abdomen of the 

 males of B. spinosvs, they apparently represent a i)henomenon inde- 

 X)eudent of the sensory bristles and their basal denticular groups of 

 spines, or both structures are so connected with each other that the 

 substituted sexual characters can be connected with the sensory or- 

 gans, for which we have to take the large ventral spines of certain ab- 

 dominal segments of the male B. sjnnosus. Beside these large spines, 

 occur, exteriorly of them, at the side of the segments, in the males as 

 well as in the females of this species, groups of minute denticular spines, 

 each with a sensory bristle. 



The last of such conspicuous characters of the variety h. of A. salina, 

 approximating this form to the genus Branchipus, consists in the fact 

 that the male claspers on the anterior ventrally-directed side near the 

 margin between the rugose protuberances and the middle have not only 

 at the sides a complex of teeth, but also that they have on these spots 

 several i)rotuberances or integumental duplicatures. It seems to me 

 that those teeth occur on that spot where certain appendages on the 

 male claspers of many species of Branchipus occur. The claspers 

 themselves are considerably smaller in the males of this Kice than in 

 the species A. salina. 



Still further on a circumstance in the biology of A. salina var. b. 

 points to the inclination of this form towards the species Branchipus. 

 It is that the males of this variety evidently occur comparatively more 

 frequently than in the other forms of Artemia. Of sixteen specimens 

 brought to me indiscriminately from the Krimea, six of them proved to 

 be males.^ Such a percentage of males I never met with in other species 

 of Artemia, among which the males are generally rare. l>rear Odessa I 

 had succeeded hitherto in finding but one female of this variety, together 

 with B. spinosus in a salt-water ditch of 4P Beaum6, none of the other 

 ibrms of Artemia occurring there. Variety h. of A. salina, however, 

 lives among all forms of Artemia known to me at the lowest concen- 

 tra,tion of salt water in salt ditches, in which live also several species 

 of Branchipus, some at higher, others at lower concentration of the 

 salt water. This circumstance is of importance, inasmuch as in species 

 of Branchipus, which do not indicate such a dilierence in figures as the 

 species of Artemia, i)arthenogenesis is unknown, while it without doubt 

 exists in Artemia, and in this number probably also in variety b. of A. 

 salina, being yat solely on the limits of the genus Artemia. Very rarely 



^ In the summer of 1876 I found in the neighborhood of Sebastopolis, in several 

 salt-water ditches and smaller salt lakes of lesser salt capacity of the water, progress- 

 ively developed generations oi A. salina; nearly half of their number were males. 



