350 W. ARCHER. 



Lesser are doubtless correct in referring the coloured globules 

 in Greeff' s forms merely to large pigment-corpuscles, not as 

 Greeff does, to " central capsules," still the outer envelope 

 does appear different to that of other Heliozoan forms. In 

 the very few forms I have been able to see this part of the 

 organism certainly' did appear to be quite homogeneous, 

 structureless, and sharply contoured externally. Once I saw 

 a form in which there were tioo, mutually sharply marked- 

 off, homogeneous and seemingly soft concentric layers, ex- 

 ternally quite smooth throughout, through which the deli- 

 cate pseudopodia projected. 



In fact, such a (single-layered) Heliozoan has not escaped 

 Hertwig and Lesser themselves, though they have not been 

 able to work it out. These authors, indeed (and I would 

 regard the record by so accurate observers of such a form as 

 a confirmation of the views here sought to be established) , 

 only give a brief mention thereof in a note (1. c, p. 224). 

 They say that " in fact Heliozoa do occur whose superficies 

 is enveloped by a homogeneous delicate stratum with the 

 aspect of but a light also, its outer limit recognised only 

 with difficulty." They figure it on t. iv, fig. 7 (1. c). Now, 

 such a nucleated, homaxial rhizopod, with its homogeneous 

 sharply bounded outer coat, as they allude to and depict, 

 is precisely my own idea of an •' Astrodisculus." 



If there be such fine openings in a silicious envelope 

 through which crude food could be incepted and the larger 

 granules expelled, as stated by Greeff, certainly in the very 

 few examples seemingly referable here which I have seen 

 no such characteristic could be detected and nothing of such 

 an appearance is depicted by Greeff himself; it appears to 

 me that during such process the outer envelope must just 

 simply temporarily give way. It is certainly a pity that the 

 forms seemingly referable here are so extremely rare in their 

 occurrence that an opportunity so much needed to submit 

 them to experiment but very rarely offers itself. 



Now, I fancy such aform may, as it were,represent a Pompho- 

 lyxophrys (= Hyalolampe) loithout the peripheral spherules, 

 but with some such an external stratum, perhaps, indeed, of 

 more dense nature than such as one may suppose to hold 

 together the globules of the latter genus, and thus differing, 

 on the other hand, from Heterophrys in the homogeneous 

 (not granular), non-mobile, and non-fimbriate character of 

 the outer envelope ; for one may suppose that the spherules 

 of Pompholyxophrys, just as the acicular spicules of Raphi- 

 diophrys, would hardly of themselves, without the presence 

 of some connecting medium, of however great tenuity, 



