PACKARD. ] TRANSFORMATION OF ARTEMIA. 473 
of Branchipus spinosus groups of dentate spines occur only on the ventral 
side of the postabdomen just before the articulation. 
In the same places fine bristles arise out of groups of circulatory cells 
in Artemic living in salt water of high density, which cells, by domes- 
tication of several generations of Artemia in gradually diluted salt 
water, transform into groups of small dentate spines. 
3. Under the name of postabdomen I mean the last nine segments of 
the posterior section of the body, or all apodous segments which are 
frequently called postabdomen. Artemia has eight such segments. 
After all, it seems to me that not all apodous segments deserve 
either the term abdomen or postabdomen, since the first two segments, 
bearing the external genital organs, are more sharply defined or insected 
from the following segments, being also somewhat shorter and broader 
than the latter, having therefore more resemblance with the precediug 
limb-bearing segments. 
It appears to be more proper to add the two connate genital seg- 
ments to the preabdomen, calling postabdomen all the other apodous 
segments; this view concurring also with the developmental history. 
According to the latter view we have seven apodous segments in 
Branchipus and six in Artemia. 
D.—CONTRIBUTION TO A KNOWLEDGE OF THE INFLUENCE 
OF EXTERNAL CONDITIONS OF LIFE UPON TLE OR- 
GANIZATION OF ANIMALS. 
By WLADIMIR SCHMANKEWITSCH.! 
{Translated by Dr. C. F. Gissler.] 
I published in 1875 in the Russian language, in the Transactions of 
the Neo-Russian Society of Naturalists (Vol. III, 2d part), a paper under 
the title “‘Some Crustaceans of the salt and fresh waters, and their rela- 
tion to the surrounding elements.” ? 
After the further elaboration of the material, I shall publish the entire 
contents of my labors, at present submitting only the part which I re- 
gard as the more complete. 
I.—Some instances illustrating the influence of salt-lake surroundings 
upon the life and develupment of several crustaceans. 
1 Zeitschrift fiir Wissenschaftliche Zoologie, XXIX, 429-494, 1877. 
2 The contents of the paper are the following: Chapter I. The genus Cyclops (€. bicus- 
pidatus Cls. and C. odessanus n. sp.. C. brevicaudatus Cls., C. brericornis Cls., C. serrulatus 
Fischer. C. tenuiformis Cls., C. minutus Cls.). Enumeration of the species and races 
of this genus from the neighborhoou of Odessa. Diagnosis of the undescribed forms 
of Cyclops. The indication of forms necessary to compare the characters of the known 
species of this genus. General remarks on Cyclops brevicornis and C. brevicaudatus. 
Effect of the surrounding element upon the forms of Cyclops under artificial domesti- 
cation. Chapter II. Cletocamptus genus noyum (family of Harpactidée), Cl. strémii 
and Cl. retrogressus, and domestication of the latter in changed surroundings. Chap- 
ter III. Transfuga gen. novumn (fam. Harpactide), Tr. salinus n. sp., and Zr. lacustris 
n.sp. Chapter lV. The relations between marine forms and fresh-water forms in the 
family of Harpactide. Chapter V. The genus Daphnia. D. magna Leyd. varietas, D. 
rectirostris Leydig ( Moina reclirosiris Baird) of salt and fresh waters. Daphnia degenerata 
n. sp. and D. rudisn. sp., both marine forms. Chapter VI. The genera Artemia and 
Branchipus. Artemia salina Milne-Edwards. The gencrations of Artemia salina receiv- 
ing the characters of Art. Milhausenti. Branchipus ferox Chyzer varietas. Branchipus 
spinosus Milne-Edw. Branchipus medius mihi. The characters of the genera Artemia 
and Branchipns. The transformations of the branchial sacs and posterior gill-lobes 
in Artemia and Branchipus under the influence of the surroundings. 
