345 



Öfversigt af Kongl. Vetenskaps-Akademiens Förhandlingar, 1894. N:o 8. 



Stockholm. 



Notes on the formation and absorption of the skeleton 

 in the Echinoderms. 



By Hjalmar Théel. 



[Communicated 1894, October 10.] 



During a stay last sumnier at Kristineberg, the Swedish 

 marine biological station, the ohject of my researches was the 

 development of various organs in the Echinoderms; my results 

 will be published låter. Whilst occupied with these investiga- 

 tions I had frequent opportunity of perceiving on living speci- 

 mens how the larval calcareous rods were formed and absorbed 

 again, and of following the activity of the operative cells. See- 

 ing that Chun ^) recently wrote a paper giving his results of 

 observation of the formation of the calcareous bodies in the 

 Auricularia larvae — which results do not agree with mine;^) 

 moreover seeing that the literature on the subject scarcely af- 

 fords any information on living cells in the process of absorbing 

 calcareous bodies, it is thought the following communication 

 may be of sonie interest. 



It is a well-known fact that the amoeboid or naked cells, 

 termed migratory or wander cells, leucocytes, påle or colourless 

 corpuscles, lymphoid cells and even phagocytes, play a very 



^) Die Bildung der Skelettheile bei Echinodermen. Zool. Anzeiger XV. 1892. 



pp. 470—474. 

 *) On the development of Echinocyamuß pusillus. Nov. Acta Reg. Soc. Sc. 



Upsala. Ser. III. 1892. 



