ARKIV FÖR ZOOLOGL 



BAND 13. N:o 25. 



On amoebocytes and otlier coelomic corpuscles 

 in the perivisceral cavity of echinoderms. 



III. 



Holotluirids. 



By 



HJALMAR THÉBL. 



With 7 plates and 7 text-figures. Read November 10 1920. 



In two earlier papers published in Swedish (Arkiv för 

 zoologi, Bd 12, N:o 4 and 14, Stockholm 1919) I accounted 

 for my investigations on the amoebocytes of some echinoderms, 

 especially on those of Asterias rubens and Parechinus miliaris. 

 In conformity with my primary plan, I also intend in this 

 third pap.er to pay special attention to the true white leuco- 

 cytes with long pseudopodia, because, according to my opinion, 

 they play a very important part in the life of echinoderms, 

 possibly in a higher degree than in that of many other animals. 



Considering that the two former reports were published 

 in Swedish it is more than likely that their contents may be 

 misinterpreted or rather ignored. That is the reason why 

 I now prefer to send forth this third part in English. I do it 

 all the more as it is highly desirable that views, sucli as those 

 expressed by me, may be subject to a careful criticism. Lately 

 some distinguished english investigators, Edwin S. Goodrich 

 (1919), John Tait and John Tait & I. Donald Gunn (1918), 

 have published interesting papers on the leucocytes belonging 

 to different orders of invertebrates. Though they have treated 

 their material from views somewhat different to my own, 

 the results of our almost simultaneously executed researches 

 agree in some respects, not in all, however. Therefore, a 

 revision seems to be very desirable. 



Ävkio för zoologi. Bd 13. N:o 25. 1 



