Academy of Science); two years later an article followed in 

 NACHRICHTEN VON DER GESELLSCHAFT ZU GOTTINGEN. The 

 data mentioned there, apparently, did not convince Krohn. In 

 1871 in ARCHIV FUR MIKROSKOPISCHE ANATOMIE, edited by 

 Max Schultze, a new work by Kovalevsky was published, 82 a t 

 which time Schultze added the following postscript to a letter 

 directed to Kovalevsky on January 18,1871: "Krohn, who read 

 your article in proof and made minor corrections, sends you 

 heartfelt regards. At first he was, as you can imagine, very 

 much against the relationship with vertebrates; 83 b u t then he 

 began to hesitate." 84 



Krohn was one of the pioneers of zoological investiga- 

 tions on the Mediterranean coast, which later became a place 

 of pilgrimage for naturalists from different countries of 

 Europe. 



It is highly probable that Kovalevsky and Mechnikov were 

 well acquainted with the works of Krohn. His remarkable 

 comparative embryological investigations, of which they became 

 aware in the mid-1860s, revealed the nature of Krohn 1 s 

 scientific activity and produced an impression on them. Like 

 Krohn, they spent many years of their lives as travelling 

 naturalists, more than once following him to those localities 



82. A. O. Kovalevsky, "Entwickelungsgeschichte der einfachen 

 Ascidien," MEM. AC. SC . ST. PETERSB . , VII Ser., 10, 

 No. 15 (1866), 16 pp.? "Beitrag zur Entwickelungsgeschichte 

 der Tunicaten," NACHRICHTEN VON DER GESELLSCHAFT 

 ZU GOTTINGEN, No. 19 (1868), pp. 401 - 415? "weitere 

 Studien iiber die Entwickelung der einfachen Ascidien," 

 ARCH. MIKR. ANAT., 7 (1871), pp. 101 - 130. 



The Russian translation of the first and third articles 

 are to be found in A. O. Kovalevsky, SELECTED WORKS, 

 editor and commentator A. D. Nekrasov and N. M. Artemov 

 (Izd. AN SSSR, 1951), pp. 41 - 78 and 79 - 122. 



83. The paper was on the relationship of ascidians to verteb- 

 rates . 



84. Schultze' s letter is included in the book PEREPISKA 

 A. 0. I V. 0. KOVALEVSKY (Postscripts of A. O. and 

 V. O. Kovalevsky) , edited by A. A. Borisiak and 



S. Ya. Streich. The extract of this letter is published 

 here with the permission of S. Ya. Streich. 



597 



