did not see their separation. According to his description, 

 a number of hillocks on the animal pole of the divided ovum 

 directly turned into a thickening which is the rudiment of 

 the embryonic stripes. The embryonic stripes of Nephelzs 

 are illustrated very schematically by Rathke; he did not 

 observe the characteristic cellular rows in these stripes, 

 neither did he recognize the connection between the only 

 three teloblasts illustrated in his drawing which are 

 situated as if they lie at the extreme ends opposite to 

 the embryonic stripes and the middle one as if it lies 

 between these ends. Rathke also represented the embryonic 

 stripes of Clepsine less distinctly than Grube. 



All this is mentioned not to underestimate the 

 significance of Rathke ! s investigations, but only to draw- 

 attention to the more perfect work, in many aspects, of 

 Grube, to call to mind its priority and to show the importance 

 of his work in the history of Russian and world embryology. 



In the 1830' s and 1840' s, the development of inverteb- 

 rates also interested A. D. Nordmann (1803 - 1866). Aleksandr 

 Davidovich Nordmann was the son of a Russian officer born 

 in Finland. In 1821 he entered the university in Abo, and 

 after graduation he worked for some years in Berlin with 

 Rudolphi and Ehrenberg. During his stay in Germany he 

 accompanied Oken, Tiedemann, and Chamisso on a trip for 

 the study of sea fauna. In Berlin Nordmann published his 

 first work, MICROGRAPHICAL INFORMATION, dedicated to 

 the structure and taxonomy of parasitic worms (describing 

 many new forms, in particular "spainika" - Diplozoon paradoxwi) , 

 and also the structure and development of parasitic copepods.16 

 In 1832 Nordmann was invited to join the department of zoology 



16. A. v. Nordmann, MIKROGRAPHISCHE BEITRAGE ZUR NATUR- 

 GESCHICHTE DER WIRBELLOSEN THIERE (Berlin, 1832), 

 Vol. I, viii + 118 pp., 1: UBER BINNENWURMER IM AUGE 

 HOHERER THIERE; 2: BESCHREIBUNG EINIGER NEUEN 

 HELMINTHE. vol. II, xviii + 150 pp., 1: BESCHREIBUNG 

 EINIGER NEUEN PARASITICHEN ENTOMOSTRACEEN; 

 2: ERSTER BEITRAG ZUR NATURGESCHICHTE DER 

 LERNAEN. 



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