THEEL, THE AMOEBOCYTES BY ECHINODERMS. 7 



at some dates of the year one of the two kinds of amoebocytes 

 is predominant while the other is in minority. 



With regard to the figures 10 and 14 in the paper of 

 Goodrich I must confess that I am in suspense whether they 

 really represent the same species of amoebocytes. To judge 

 from the text, the author evidently presumes this to be the 

 case, but to my mind they ought to represent two different 

 kinds of cells, figs. 10 and 11 being identical with my bladder- 

 amoebocytes (= blåsamoebocyter) and figs. 12 — 14 being true 

 plasma-amoebocytes in my sense — ef. Ast. rub. and Parech. tnil. 



On page 21, the accoimt of Goodrich runs' as foUows: 

 »The echinoderms have long been known to possess very 'amoe- 

 boid' coelomic corpuscles. In his interesting paper on 'plas- 

 modium' formation Geddes figures the leucocytes of Echmus 

 as provided with very long, branching pseudopodia, some 

 of which join so as to encircle a space. In reality, no such 

 processes are present in fresh corpuscles, and they, like the ring- 

 like arches, are merely representations of optical sections of 

 an extensive membrane folded wdth rounded surfaces (pl. 2, 

 fig. 11). Very soon, however, af ter the coelomic fluid has 

 been removed from the animal the membrane begins to stretch 

 out mng-like films in various directions, and these soon acquire 

 a jagged edge with sharp points (pl. 2, fig. 12).» 



With regard to the named membranes of the leucocytes 

 I content myself with a reference to the figures in my former 

 accounts, from which it may be evident, that my observations 

 agree in several respects with those of Goodrich, but that 

 they differ considerably, too. 



On page 16 {Ast. rub.) I WTote: »However, it is a fact 

 that these bladder-cells (= blåsamoebocyter), besides filiform 

 pseudoj)odes, also protrude such, in the shape of thin mem- 

 branes, which, like the walls of the bladders, are hyaline and 

 structureless, but which assume a shade of blue after treatment 

 with ferro-hsematoxylin. In vertical position these membranes 

 present themselves as simple threads. Therefore, it is very 

 probable that much of that which has been taken for filiform 

 protrusions really is nothing else than filmy projections. Owing 

 to these films one gets the impression many times of the bladder- 

 cells having been torn out from any connection. » 



»It is worthy of notice that I have commonly seen the 

 bladder-cells isolated without tendency to fuse together, 



