RECENT MEMOIRS ON FRESHWATER RHIZOPODA, 71 



that the products of such fission had passed into the state of 

 zoospores. Should this procedure (i.e.^ the exit of all products 

 of subdivision) be the general one, the mode of reproduc- 

 tion here described might be simply referred back to that 

 mode by fission described by Cienkowski — the only difference 

 being that each product of division again repeatedly sub- 

 divides into two, and produces a zoospore. As regards both 

 modes, analogies are offered by Microgromia. 



That examples of this species are sometimes found seated 

 on preceding individuals, in which fact GreefFthought to see 

 an "inclination to the formation of Colonies,^' Hertwig and 

 Lesser regard as purely accidental ; and in this they coincide 

 in my own previously expressed opinion — such examples are 

 seated on those preceding them in the order of time, simply 

 because the latter afforded the nearest fulcrum for the young 

 individuals resulting from simple subdivision without passing 

 into the zoospore-state, and hence capable of but a compara- 

 tively very restricted locomotive power. 



Having thus given a resume of the foregoing beautiful 

 observations of these authors on Clathrulina, one is tempted 

 however, to urge that there hardly seems a necessity to place 

 HedriocT/stis pellucida, Hertwig and Lesser, in a separate 

 genus — that the two organisms are indeed specifically most 

 distinct, cannot for one moment be questioned. I almost 

 think this will be readily evident on looking at the authors' 

 own diagnostic characters. 



Hertwig and Lesser, in concluding their long and most 

 important work, regard it as proven that a separation of our 

 Heliozoa from the Radioloria is justifiable (and I must now, 

 as before mentioned, give my own adhesion to the view), but 

 they point out several of the lacunse in our knowledge requi- 

 site to be filled up, and certain vexed points to be settled by 

 repeated and extended researches, ere we have a complete 

 and true conception of the whole of the conditions of organi- 

 sation of the Heliozoa. Thus it would be desirable to know. 

 How far a differentiation of the body-mass into endo- and 

 ectosarc prevails in the group — Whether a differentiation of 

 the pseudopodia into a granuliferous investing stratum around 

 a homogeneous axis is a more widely spread character than 

 would as yet appear — What the mode of ending of the axis 

 and its histological significance, and last (not least) — What 

 the bearing and details of the various reproductive processes ? 

 The classification (propounded by them) of the group can hence 

 be regarded as but provisional, the more so as the relatively 

 small number of genera and species does not yet render it 



