4 ARKIV FÖR ZOOLOGI. BAND 13. N:0 25. 



cytoplasm. Within five or ten minutes (at ordinary tempe- 

 rature) they ha ve flattened out to cover an area much greater 

 than that originally occupied by them and are now very diffi- 

 cult to see. In spreading out in this fashion their cytoplasm 

 may completely fuse with that of neighbouring cells of the same 

 kind. Power of free locomotion is absent. The protruded 

 processes are not retractile. » 



However, from my above mentioned papers it appears, 

 too, that the coelomic fluid of echinoderms lodges, besides 

 different varieties of discoidal corpuscles, bipolär, tripolar 

 and multipolar cells, which represent quite another type — ef. 

 Parech. mil., pp. 25 — 27. These amoebocytes remain compact 

 and do not become flattened, nor do they spread out in a fashion 

 to cover an area of the glass greater than that originally oc- 

 cupied by them. This type seems to ha ve been totally over- 

 looked by previous investigators. 



Contrary to Tait and Gunn I therefore insist on the re- 

 taining of the old well-known term »amoebocytes» for all 

 leucocytes in the echinoderms, this all the more, as the two 

 authors must admit, that even in crayfishes the cells in question 

 are capable of presenting amoeboid movement, though in a 

 limited sense. 



Considering that my two earlier papers on the coelomic 

 corpuscles were written in Swedish, I may be allowed here 

 to translate some of my statements, which bear closer relations 

 to the quoted accounts of Tait and Gunn, and also to that of 

 Goodrich, refered to låter on. The excerpts pertain to the 

 account on the amoebocytes of Parechinus miliaris. 



Page 11. »I am fully convinced that the cells in question [plasma- 

 amoebocytes] are different in different forms of echinoderms; moreover, 

 I should not be at all astonished, when it once would be proved that 

 every species was characterized by its own special leucocytes. » 



Pages 11-12. »The hyaline [plasma-] amoebocytes pass their life 

 within the coelomic cavity of the echinids not only isolated but also 

 fused together with other neighbouring cells in order to result in the 

 formation of syncytial heaps of various form and size. . . . It is well 

 known, that such heaps are floating about in great quantities within 

 the coelomic cavity of our common starfish {Asterias rubens]. » 



Pages 18-19. »When comparing these figures [ — ef. text. fig. 3, 

 representing seven amoebocytes drawn from the living] with those 

 obtained in good preparations fixed immediately after withdrawal 



