THEEL, THE AMOEBOCYTES BY ECHINODRRMS. 



9 



F"» 



proportion to the volume of coelomic fluid. Rarely, larger 

 plasmodia may occur, which are formed by a total fusion of 

 many cell-bodies in such a manner, that no obvious traces 

 of the primitive solitude of the cells become visible. On the 

 other hand, syncytial net-works of various dimensions — often 

 made up of a few cells — are frequently met with; their meshes 

 are irregular and unequal with the bordering threads between 

 knöt and knöt represented by a single or a few pseudopodia. 



Text-figure 1. Plasnia-amoebocytes of Labidoplax buskii. Immediate 

 fixation in Perényi's solution. Length of the larger syncji:iuni 



= 68 a. 



Labidoplax buskii. 



When fixed immediately on withdrawal of the coelomic 

 fluid the plasma-amoebocytes present themselves in the 

 microscope chamber as isolated cells together with scattered 

 small syncytial bundles with protruding pseudopodial threads 

 and membranes giving the bundles a wooUy aspect, a well 

 known appearance in the coelomic fluid of Asterias rubens. 

 In thin syncytia the cells are fused together by band -like 

 membranes and thread-like pseudopodia — ef. text-fg. 1. I am 

 fully convinced that their behaviour must be taken as an 

 evidence of vital activity. 



As may be understood from figs. 3 — 6 on plate 1 andfigs. 

 1 — 5 on plate 2, the more or less isolated plasma-amoebocytes 



