32 PIlOCEEDI2^GS OF THE 



8. The Geologv of the Davos District. Quart. Journ. Gaol. 

 See, Aug. 1S99. ■ 



9. The Geology of Bad Nauheim and its Thermal Salt-springs. 

 Geol. Mag., Aug. 1900. 



In conjunction with Mr. Grenville A. J. Cole : — 



10. The Northern Slopes of Cader Idris. Quart. Journ. Geol. 

 Soc, April 1889. 



With Miss K.M. Hall: — 



11. Notes on the structure of TmesiiAerls. Proc. Eoyal Irish 

 Academy, 27 April, 1891. 



With "Mr. Griffith J. Williams :— 



12. On the Geology of Manod and the Moelwyns, North Wales. 

 Quart. Journ. Geol. Soc, Aug. 1891. 



Alexander Kowaletskt, the eminent Russian biologist, ^^■as born 

 in 1840. He belonged to a family of which two other members 

 attained scientific distinction : his brother Vladimir as a palaeont- 

 ologist, and his cousin Sophie as a mathematician. 



In his seventeenth year, after a brief period of study in the 

 St. Petersburg University, Alexander Kowalevsky went abroad, 

 first working at chemistiy in Bunsen's laboratory in Heidelberg, 

 and then studying zoology under Leydig at Tiibingen. In 1864 he 

 went to Naples, where he worked Avith such ardour and success 

 that, at the eai'ly age of twenty-six, his name became well-known 

 .among biologists. 



Russian biologists were among the first to recognize the great 

 significance of the Evolution theory in the domain of Embryology, 

 and the chief advance made in this science during the sixties was 

 due to Kowalevsky and MetschnikofF. 



In 1866, Kowalevsky pubhshed two closely allied series of 

 researches on the development of Amphioxus and on that of the 

 Ascidians, works which are remarkable not only for the novelty of 

 the results obtained but for great clearness and accuracy. Kowa- 

 levsky demonstrated the presence of the notochord in Aseidian 

 embryos and caused quite a sensation by showing that these animals, 

 until then supposed to be invertebrates, belong to the vertebrate 

 phylum. 



In 1868, Kowalevsky was appointed professor at the Kazan 

 Ujiiversity ; he remained there only one -year, during which he 

 published his " Embryological Studies on the Worms and the 

 Arthropoda," a work which testifies to marvellous energy and 

 resolute conquest of difficulties, at a time when microtomes were 

 hardly known and when carmine was the only stain. These 

 embryological stvidies were epoch-making ; they established the 

 uniformity of the first processes of development in all multilaminar 

 animals and overthrew many views then prevalent. In Worms 

 and Ai'thropods, as in Vertebrates, Kowalevsky demonstrated the 

 laying down of the organs in the form of germinal layers, these 

 latter containing the rudiments of the whole complex of organs. 



It was Kowalevsky wdio discovered in Phoronis, the Ctenophora, 

 Sagitia, Lumbricus, and the Brachiopoda the embr3^onic stage since 



