LINNEAN SOCIETY OF LONDOX. ^;^ 



•well known as the Gastnda stage. Haeckel utilized his observations 

 wlien he propounded his Gastro; theory. Kowalevsky himself, 

 who only drew conclusions from strictly verified fact.s, refrained, as 

 ii rule, from theorizing. Another well-known theory, the ccelomic 

 theory, was founded on Kowalevsky'.s discovery that, in Ampliioxus, 

 Surjkta, and the Bracliiopoda, the mesoderm develops in the form 

 of protruding sacs from the ectoderm. He himself recognized the 

 .significance of this discovery, but considered the establishment of 

 a hypothesis premature. 



In 1S69, KovvaleAsky accepted a professorship at Kieff, where 

 he was an active member of a new Society of Naturalists, to which 

 he contributed many of his discoveries, among others that of the 

 connection which exists betw een the alimentary and the spinal 

 canals in the embryos of Sharks. This observation led to the 

 revelation of a similar connection in all Vertebrate embryos. 

 To this Society also, Kowalevsky communicated his discovery of 

 the planaria-like female of Bonellia, vvhicli differs so greatly 

 from the male form ; also the observations on the budding of 

 Perophora, which have formed the basis of all more recent investi- 

 gations into the budding of the Ascidiaus. Other papers threw 

 important light upon the connection between the asexual processes 

 of multiplication and the metagenesis of the Salpidae. 



It was during Jvowalevsky's sojourn at Kieff that the Brachio- 

 poda, which were then classed as Molluscs, were carefully in- 

 A'estigated by him. With this object, he visited the Eed Sea and 

 Algiers, ardently pursuing his researches under great difhculties, 

 spending days and nights in the boats of coral-fishers, sharing 

 their poor fare and exposing himself to the burning sun and other 

 discomforts. The brilliant results he obtained still place him in 

 the first rank among investigators of this group of animals, which 

 were considered by him to be closely related to the worms. 



In 1873 Kowalevsky accepted a chair in the Odessa University, 

 and while there studied many marine forms, investigating the 

 ontogeny of the Hydroids, the Acephala and the Actinia, the 

 Alcyonaria and the Lucernaria, and many Molluscs. 



From 188-1 and onward, Kowalevsky worked on a somewhat 

 difterent plan. Without renouncing morphological work, for he 

 produced after this date excellent monographs on the metamor- 

 phoses of the Diptera and the development of the Scorpions and 

 the Solpugidse, he took up questions bordering on physiology and 

 anatomy. He published many treatises elucidating obscure organs 

 in various Invertebrates, using the method of injecting colouring- 

 matter into the living organism, and thus revealing whole series of 

 organs until then unknown, but of great significance for the life 

 of the animals in their conflict with micro-organisms. These 

 he called the blood-cleansing organs. 



In 1890 Kowalevsky settled in St, Petersburg at the Academy 

 of Sciences, and while there laboured indefatigably in collecting 

 funds for and oi'ganiziug the Marine Biological Station at 

 Sebastopol, which he believed woidd be of great value as a centre 



LEfX. SOC. PROCEEDINGS. —SESSION 1902-1903. d 



