284 Mr. H. J. Carter on the Fresh- and Salt-water 



natural, or -induced by pressure of the glass cover, I have not 

 yet been able to decide. In one instance, after a matured 

 spherule had been forced out of the parent, I observed that the 

 transparent cell, which does not exceed it much in size, contained 

 a fine delicate plasma, in the midst of which there was a single 

 vacuole ; and I could not help also seeing in this specimen the 

 same elementary composition as that of an Actinophrys, viz. 

 a thick endosarc with strongly marked granules, surrounded by 

 a thin ectosarc in which there was a vacuole like a contracting 

 vesicle. Whether that be the body, and these be the elements 

 respectively which afterwards become developed into a young 

 Actinophrys, is for future observation to determine. Crude food 

 is incepted by A. Eichhornii, and contracting vesicles appear here 

 and there ; but I never could detect a nucleus in either the largest 

 or the smallest specimens (fig. 7) that I have had under my 

 observation. 



It is true that, in the figure which I have given of A. Eich- 

 hornii found at Bombay, bodies are drawn which I conjectured 

 to be respectively the nucleus and reproductive cells ; but, as 

 there is nothing so situated in the A. Eichhornii which I have 

 been studying in England to identify with such bodies, the state- 

 ment must be only taken for what it may prove worth hereafter. 

 It is worthy of note, however, that Claparede says (op. cit. 

 p. 452, foot-note), " En A. Eichhornii le nucleus est, au con- 

 traire, toujours facile a reconnaitre." This certainly was not 

 the case with any of the specimens of A. Eichhornii, small or 

 great, that came under my notice; but then it might have been 

 obscured by the vacuolation ; for in another form of Actinophrys, 

 which was also present, although not plentiful (viz. fig. 8), and 

 even smaller than fig. 7, it was most evident in the endosarc, 

 which was surrounded by a clear layer of ectosarc, bordered by 

 a wrinkled margin or surface; but then there was no vacuolation. 

 Probably if the vacuoles in the smaller forms of A. Eichhornii 

 had been broken down, and the nucleus sought for in this way, 

 it might have been observed ; for I cannot help thinking that, 

 at least when the spherical bodies are not present, there must be 

 a nucleus. 



Again, the absence of the nucleus, when the spherical bodies 

 become numerous and fully developed, may be accounted for by 

 its having passed into a brood of germ-cells, and its having thus 

 become effete, as described and illustrated in Difflugia (Annals, 

 vol. xiii. pi. 1. figs. 2, 3, 4, &c). 



When, then, we view an old Actinophrys with between three 

 and four hundred of these spherules in her body, relatively ana- 

 logous to, and absolutely of nearly the same size as those which 

 I have already shown to exist in all the other Rhizopoda above 



