3G4 W. ARCHER. 



the basal plates of the spines, but without being attached to 

 them. They frequently moved in a tremulous manner, in 

 little oscillations, or passed up and down by the pseudopodia ; 

 the authors even saw some of them, wholly detached from 

 their place, betake themselves, with a vigorous move- 

 ment amongst the spines, to some other part of the super- 

 ficies. They could perceive nothing of cilia or other motory 

 organs. There was no perceptible attachment of the globules 

 to the body ; they once, however, saw some of these, along 

 with two of the spines, pass upwards by a pseudopodium, 

 but in connection with neither, yet with the same rapidity 

 as the spines. It gave them the impression as if these were 

 drawn forwards by an extraordinarily delicate, imperceptible, 

 thread of protoplasm. The authors were quite unable to offer 

 any explanation of this phenomenon, merely recording the 

 observation in the mean time on account of its curiosity. 



Could this be a parallel (and equally puzzling and inex- 

 plicable) for the observation I myself recorded' as regards 

 an as yet unnamed rhizopod (scarcely Heliozoan), where 

 certain corpuscles were suddenly and simultaneously " shot 

 off" in a volley all round the periphery of the body-mass, 

 then somewhat slowly retracted and reimbedded therein ? 

 Unless these corpuscles were retained and drawn back by 

 (invisible) protoplasm-threads, they would, one would sup- 

 pose, have been projected beyond recall. 



A. spinifera, Greeff.^ (Fig. 8.) 



In this species (whose structure and details are now so 

 well known, it is unnecessary here to enlarge thereupon) 

 it was that Hertwig and Lesser were able most clearly to 

 see the evident line of demarcation between endosarc and 

 ectosarc. Into a mistake in this regard doubtless I myself 

 have fallen in taking this inner region for "central capsule;" 

 and I certainly now feel I have done so in taking the true 

 nucleus for the representative of the " inner vesicle" {vesi- 

 cula irdinia or *' Binnenblase ") . Nor am I alone in this, for 

 Greeff shortly afterwards, I find, had propounded the same 

 views. But Greeff went further and stated that the pseudopodia 

 were traced by him to be continued inwards, and to be in 

 connection with this inner region, his " apparent equivalent 

 to the central capsule," being one and the same with Hertwig 

 and Lesser's endosarc. Could what Greeff records he was 

 able to perceive thus so far reaching inwards have been an 

 " axis" equivalent to that of Actinosphserium ? if so, that 



^ ' Quart. Journ. Micros. Sci.,' n. s., vol. xv, p. 114. 



» Greeff, in ' Schultze's Arcbiv/ Bd. v, p. 493, t. xxvii, f. 20. 21. 



