^96 W. ARCHEll. 



the central capsule of Acanthometridse as but conjectural. In 

 this 1 must -wholly coincide with Hertwig and Lesser. 



How far this central axis of the pseudopodia is extended 

 amongst Heliozoa is questionable ; if generally present it is 

 certainly extremely difficult of detection. 



The skeleton sometimes consists of a single solid and 

 globular piece — sometimes (and more frequently) of numerous 

 loosely combined pieces, globularly distributed. The latter 

 are mostly bacillar, and if tangental in position are denomi- 

 nated " spicules," if radial '' spines." Some (Actinophrys, 

 Actinospheerium) are destitute of any skeleton. 



The locomotion of a Heliozoan is a very slow one; it 

 balances itself on the apices of the pseudopodia, and by help 

 of their contractions rolls (very slowly) onwards. 



Any propagation known is asexual — simjile fission qf the 

 body-substance, distinguishable, however, into two modes : 

 that is, division of the naked body or division within a cyst. 

 The individual portions originating in the latter manner 

 become once more themselves encysted. 



The daughter individuals arising by division either pass 

 at once into their persistent form or go through a zoospore 

 stage, assuming an ovoid figure, and developing at one end 

 two flagella. In Ciliophrys, Cienk., the whole organism 

 passes directly into a zoospore condition. None of these 

 modes of development seem to have a generic or specific sig- 

 nificance. Thus from the cjstsofActinophi'ys sol comedirectly 

 young individuals of Actinophrys ; on the other hand, zoo- 

 spores from the cysts of Clathrulina. The subdivision of the 

 non-encysted Clathrulina body sometimes produces zoo- 

 spores, sometimes directly young Clathrulinse, establishing 

 themselves at once on leaving the mother individual. 



Heliozoa Askeleta. 



The great character of these must be regarded the spherical 

 figure, combined with the absenceof any skeleton. 80 great 

 stress do Hertwig and Lesser lay on the former character 

 that if a rhizopod, though sometimes globular, habitually 

 assumes an irregular figure, and during locomotion under- 

 goes amoeboid modification of contour, they would exclude 

 such from this subgroup. Thus they would not refer 

 Nuclearia, nor Leptophrys, nor Vamj)yrella, even if it had a 

 nucleus, hither -, and in this I feel they are perfectly right. 

 There is a steadiness, so to say, of form, or there is a cha- 

 racteristic jjolymorphism evinced by each of these lowly 

 organisms which seems wonderfully inherent. 



