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HJALMAR THÉEL: ACTIVITY OF AMOEBOID CELLS IN THE ECHINODERMS 





The above remarks may be sufficient to prove that the absorption and de- 

 struchon oj the skeleton in the Echinoderms go on hand in hand with new formation 

 of calcarious substances, and that these processes are facilitated by the d, 

 being directly transferred through the pseudopodial intercommunication from one ; 



to another. 



Wood-cut Xo. II represents the middle part of the posterior portion of another pluteu 

 the calciferous cells (d) have just begun to deposit a minute calcarious particle. They .... in I 

 with those cells which absorb the broken end-pieces of the rods (<•). 



Our present knowledge of the ostoclasts in vertebrates is ver)' defective. 

 As far as I know, we are completely in the dark as to their mode of operation and 



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In wood-cut No. Ill only a middle part of the posterior end of the pluteus is drawn 

 stomach being left out. Considering that the broken end-pieces of the rods have been totally absorbed 

 the calciferous cells receive abundance of calcarious salts through long, brain lud | dia which 



with cells which exercise their dissolving influence upon the ends of the supporting rods themselve 

 rods are not drawn on the figure, wherefore I refer to wood-cut No. i (b). 



how the salts are transferred to the obstcoblasts in order to supply them with cal- 

 carious material enough to operate most effectively. Possibly a hint is given by the 

 studies of Echinoderms? 



Festshrift für Lilljeborg. 



