THÉEL, THE AMOEBOCYTES BY ECHINODERMS. 15 



judge from his figures 10 and 11 on plate 2, he evidently saw, 

 but misinterpreted t hem. 



2. — Af ter removal from the animal, they do not change 

 in any noticeable way within the microscoj)e-chamber, neither 

 do they flatten out, nor do they spread on the surface of the 

 glass slide »to cover an area much greater than that originally 

 occupied by them». 



3. — The bladders do not change place within the cell, 

 which, on the contrary, is the case with the sj)erules or grannles 

 of the »amoebocytes with sperules»; they are irregular in form, 

 different in size, and placed in two or three snperposingplanés; 

 now and then, bladders are met with which are extended in 

 length, and curved in such a manner, that the two ends for 

 inst. are visible in an upper plane, while the middle-part of the 

 cnrve is seen in an under plane; in such a case oneistempted 

 to think that one has to do with three different bladders. 



4. — In Asterias ruhens^, to which I paid special attention, 

 the bladder-cells vary greatly in number; in some specimens 

 they are predominant, seemingiy on the cost of the plasma- 

 amoebocytes, in other specimens, on the contrary, the case 

 is reversed. This caused me to become suspicious, whether 

 the two kinds of amoebocytes really were distinct, or rather 

 representing different states of the same cell under perf ormance 

 of different functions. 



5. — The bladder-amoebocytes are lighter than the plasma- 

 cells^ When removed from the coelomic cavitj^ of a starfish 

 into a tubular glass, the corpuscles separate; the plasma- 

 cells, having a relatively high specific gravity, sink through 

 the fluid to the bottom of the tube more rapidly than the 

 bladder-cells, which first låter on form a layer upon them. 



Amoebocytes with spherules. 



Granular tliigmocytes, Tait." 

 Amoebocytes, Tait and C4unn.' 

 Kulamoebocyter, Théel.* 



I readily admit, that I have attached very little importance 

 to the behaviour of these cells in the holothurids, and conse- 



* Op. cit., pp. lo — 20. 

 ^ Op. cit. 1919. 



■' Op. cit. 1919. 



* Parech. mil. 1919, pp. 30—39. 



