Rhizopoda of England and India. 279 



With A. ocidata were associated groups of A. Sol, mini (fig-. 3), 

 differing only from those of A. ocidata in the absence of the 

 nucleus and the strongly marked crenulated outline round the 

 Actinophryans, with less appearance of uniting sarcode, but 

 more of actual zygosis. Their internal contents, too, consisted 

 almost wholly of the characteristic granular sarcode of Actino- 

 phrys, with complete absence of all vacuoles, even to the con- 

 tracting vesicle itself — a condition most favourable for seeing 

 the nucleus, if it had been present ; but none was detected. 



A complete disappearance of the nucleus (termed its " solu- 

 tion ") and its reconstruction are not uncommon. It would seem 

 to occur in duplicative division of the cells of Spirogyra nitida, 

 &c. (A. Braun, Bot. and Phys. Memoirs, Bay Society, 1853, 

 p. 24-1 ; and Nageli, foot-note, p. 248) ; also, under similar 

 circumstances, in the addition of new to the old tubular root- 

 cells of Char a verticillata (Annals, vol. xix. p. 13) ; and latterly 

 its disappearance has been demonstrated and explained in some 

 of the freshwater Rhizopoda themselves, as in all probability 

 connected with impreguative generation (Annals, vol. xix. 

 p. 13). 



Hence this form of Actinophrys may represent a stage in the 

 generative development of A. oculata. But, whether or not, it 

 was abundantly present with A. ocidata, and will be seen by the 

 figure to be so like it in grouping that I think it may reason- 

 ably be assumed to be only another form of this species. In- 

 deed, according to Claparede and Lachmann (Etudes sur les 

 Bhizopodes, p. 45, &c), these distinguished authors could never 

 see the nucleus in A. Sol with certainty, and they add, — 

 " Stein's A. oculata is a marine form ; but we have observed 

 in the North Sea myriads of an Actinophrys that we did not 

 know how to distinguish clearly from A. Sol of the fresh water, 

 and which coincides altogether with the figure given by Stein of 

 his A. oculata" It is not quite evident here how A. Sol can 

 "coincide" altogether with Stein's A. oculata, if a nucleus could 

 not be seen in the former. But the authors' meaning is plain, 

 viz. that they thought A. Sol of the North Sea and A. oculata 

 to belong to the same species, which harmonizes with what I 

 have just stated respecting this question, and what my figures 

 illustrate. 



In the representations which I have given of A. oculata, fig. 1 

 is shaded, while fig. 2 is only an outline of nine individuals in 

 aggregation, with two vacuoles containing each the remains of 

 a rotatory animalcule, and the other the apparently amylaceous 

 body to which I have alluded. In fig. 1 all the tentacles bore 

 drop-like masses of cctosarc along their shafts respectively; but 

 thes e have only been inserted in those of the Actinophryan a, 



