larvae with the early stages of vertebrates . . . apparently 

 removes the difference between the main groups of the animal 

 kingdom and makes obvious what has been accepted by many 

 authors subsequent to Darwin, that the transition is made 

 from lower forms into absolutely higher forms" (p. 3). How 

 great the attention attracted by Kovalevsky's paper was, 

 Baer judged by London's QUARTERLY JOURNAL OF MICROSCOPICAL 

 SCIENCE, which as a rule printed only original papers, but made 

 an exception for Kovalevsky's paper and published a transla- 

 tion of it practically in full. 



30 

 Baer then referred to the investigation of I. I. Mechnikov, 



"also an experienced embryologist," and in particular to the 



data of K. Kupffer which he stated in a letter to M. Schultze 



and which were confirmed by the latter, and attached to 



Kupffer 's detailed article, "Already the name itself," Baer 



wrote, "'the genetic relationship between Ascidiae and 



vertebrates, '31 indicates the importance of the results received. 



The factual data and Kovalevsky's interpretations concerning 



the coincidence of the development of ascidiae and vertebrates, 



were confirmed and partially made more accurate" (pp. 4-5). 



Further on Baer noted this relation to Kovalevsky's discovery, 



which Darwin had mentioned in THE DESCENT OF MAN, and cited 



the following passage from this work: 



Kovalevsky has lately observed that the larvae of 

 Ascidians are related to the Vertebrata, in their 

 manner of development, in the relative position of 

 the nervous system, and in possessing a structure 

 closely like the CHORDA DORSAL IS of vertebrate 

 animals .... Thus, if we may rely on embryology, 

 ever the safest guide classification, it seems that 



30. I. Mechnikov, "Observations on the development of some 

 animals (Bothryllus and solitary ascidiae)," IZV. 



PETERSB. AKAD. NAUK (1869), 13, pp. 284-300. 



31. K. v. Kupffer, "Die Stammverwandschaft zwischen Ascidien 

 und wirbelthieren," ARCH. MIKR. ANAT . (1870), 6. 



481 



