M. H. Rathke. A native of Danzig, Rathke in 1829 arrived 

 in Russia, where he was professor for six years at Dorpat 

 University. Before that, he published many embryo logical works, 

 including a valuable work on the development of crayfish. 3 

 During his tenure at Dorpat, Rathke visited Moscow and 

 Petersburg and also travelled in the Crimea to investigate 

 the fauna of the Black Sea. On the Black Sea coastline, 

 Rathke collected comparative embryological material which 

 was later used in ON MORPHOLOGY: TRAVEL NOTES FROM 

 TAURIA.4 in this collection, in addition to brief information 

 about the embryonic stage of actinia, there is also an essay 

 on the embryology of the Crimean scorpion and investigations 

 concerning the development of nine species of Crustacea of 

 different orders (copepods, araphipods, decapods, and isopods) . 

 Rathke 1 s work on crayfish development, and also his investiga- 

 tions on the development of other arthropods (124), represent 

 a clear interest in describing the phenomenon of embryonic 

 development in arthropods according to the ideas of Pander and 

 Baer. Rathke spoke of the embryonic disk or blastoderm, of 

 the primary cavity, and of the two embryonic membranes (serous 

 and mucous) into which the blastoderm is divided. The first 

 stages of development, the division of the ovum and the first 

 processes of separation of the rudiments, remained untraced. 



It must be borne in mind that a clear presentation about 

 the essence of the processes which take place in the early 

 stages of embryonic development — i.e. first of all the process 

 of division — was not yet established in the first forty years 

 of the last century. Thus, Reichert (125) studied the develop- 

 ment of the frog ovum but reached an incorrect conclusion 

 about the structure of the still-undivided ovum, supposing 

 that it consisted of many cells (by cells he meant the round 

 accumulations of the yolk plates) . This point of view was 

 raised by Reichert both in his DIE ENTWICKELUNGSLEBEN 

 IM WIRBELTHIRREICH and in an article published one year 

 before, "On the Process of Division in the Ova of Amphibia, "5 



3. H. Rathke, UBER DIE BILDUNG UND ENTWICKELUNG DES 

 FLUSSKREBSES (Leipzig, 1829) , 97 pp. 



4. Rathke, ZUR MORPHOLOGIE. REISEBEMERKUNGEN AUS TAURIA 

 (Riga und Leipzig, 1827) , 192 pp. 



5. K. B. Reichert, DIE ENTWICKELUNGSLEBEN IM WIRBELTHIER- 

 REICH (Berlin, 1840), x + 261 pp.? "Uber den Furchungsprozes 

 der Batrachier," ARCH. ANAT . PHYSIOL. (1841), pp. 523 - 

 541. 



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