PACKARD.] TEANSFORMATION OF ARTEMIA. 473 



of BrancMpus sphwsus groups of dentate spines occur only on the ventral 

 side of the postabdomen just before the articulation. 



In the same places tine bristles arise out of groups of circulatory cells 

 in Artemkc 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 tirst 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 preceding 

 limb-bearing segments. 



It appears to be more proper to add the two connate genital seg- 

 ments to the i^rseabdomen, 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.— COi!^TEIBUTION TO A KI^OWLEDGE OF THE INFLUENCE 

 OF EXTERNAL CONDITIONS OF LIFE UPON TUE OR- 

 GANIZATION OF ANIMALS. 



By Wladimir Schmankewitsch.i 

 [Tranalated by Dr. C. F. Gissler.] 



I published in 1875 in the Russian language, in the Transactions of 

 the Neo-Eussian Society of Naturalists (Vol. Ill, 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. — ISome instances illustrating the influence of salt-IaJ:e surroundings 

 upon the life and development of several crustaceans. 



1 Zeitsclirift fiir Wissenschaftliche Zoologie, XXIX, 429-494, 1877. 



-The conteDts of the paper arc the following: Chapter I. The genus Cyclops {Chicus- 

 pidatus Cls. and C. odessanus n. sp., C. hrericaudatus Cls., C. brericoruis C\s., C. serrulatus 

 Fischer. C. teimiformis Cls., C. vrinutus Cls.). Enumeration of the species and race'^ 

 of this genus from the neighborhood of Odessa. Diagnosis of the iindescribed forms 

 of Cyclops. The indication of forms necessary to comi>are the characters of the known 

 species of this genus. General remarks on Cyclops brericomis and C. brcvicaudcttus. 

 Effect of the surrounding element upon the forms of Cyclops under artificial domesti- 

 cation. Chapter II. Cleiocampt>is genus novum (lamily of Harpactida;), CI. stromii 

 and CI. retroriressus, and domestication of the latter in changed surroundings. Chapi- 

 ter III. Traitsfitga gen. novutri (fam. Harpactidjc), Tr. aalhius n. sp., and Tr. lacustris 

 n. sp. Chapter IV. The relations between marine forms and fresh-water forms in the 

 family of Harpnctidce. Chapter V. The genus Daphuia. D. magnaljejd. varietas, D. 

 rectirostris Leydig ( Moina reclirosiris Baird) of salt and Iresh waters. Daphnia defjcneraia 

 n. sp. and D. rudis n. sp., both marine forms. Chapter VI. The genera Artemia and 

 Branchipus. Artemia saUna Milne-Edwards. The generations oi Artemia salina receiv- 

 ing the characters of Art. Milhaiisenii. Braiicldi^us ferox Chyzer varietas. Branchipus 

 spiiwstis Milue-Edw. Branehipm medius mihi. The characters of the genera Artemia 

 and Branchipus. The transformations of the branchial sacs and posterior gill-lobes 

 in Artemia and Branchipus under the influence of the surroundings. 



