HELIOZOA 



29 



have a large number of stiff pointed pseudopodia sticking straight 

 out all round them, like the conventional rays in pictures of the 

 sun. The common and scientific names are taken from this circum- 

 stance. Since these animals float about, it is not surprising to 

 find much the same structure in the outer protoplasm as we found 

 m Radiolaria and the floating Thalamophora. The pseudopodia are 

 different in character from those of the Thalamophora, since they do 

 not interlace, nor do they run together when they seize prey ; the 

 captured food is simply pressed in towards the body by the 



A 



FIG. 7. Various stages of Chondrioderma difforme. From Strasburger. 

 A. Flagellula leaving cyst. B & C. Flagellulae. D young and E older 

 amoebulae. F. Amoebulae fusing to form plasmodium. All x 540. 



G. Plasmodium x 90. 1. Nucleus. 



bending of the pseudopodia, and when it is brought quite close, a 

 broad irregular pseudopodium, like one of those of Amoeba, shoots 

 out and engulfs it. Pseudopodia were defined in the case of 

 Amoeba as irregular projections shot out at intervals from the body 

 and soon withdrawn, and the question arises how far we have any 

 right to call by the same name these stiff projections of the Heliozoa. 

 They are, however, true pseudopodia, for if the animal be sub- 

 jected to strong irritation they are all withdrawn. These animals 

 show a most interesting example of the repetition of parts. The 

 species Actinophrys sol and Actinosphaeriwn, eichhornii are both 



