Rhizopoda of England and India. 285 



mentioned, we can hardly doubt that they are of the same kind, 

 and that they arc an impregnated brood of reproductive cells, 

 which, in like manner, will end, on becoming matured, in the 

 death of the parent, as in the closely allied Myxogastres (My- 

 cetozoa of A. de Bary), ex. gr. JEthalium, where the prolific 

 mother lives but to become at last a dead receptacle for the 

 future welfare of her numerous progeny. 



The family of Saprolegniese are closely allied to that of the 

 Myxogastres among the Fungi; and in the former Pringsheim 

 has placed his Pythium entophytum, which, among other Algre, 

 infests the cells of Spirogyra, wherein I found its locomotive 

 rhizopodous form to be so like Actinophrys, and, as before 

 stated, the endoplasm of Spirogyra to be so like that of the 

 latter, that I was led into the erroneous view, long since cor- 

 rected, that the endoplasm of Spirogyra did thus actually become 

 transformed into Actinophrys. This, then, will give the reader 

 an idea of the position of A. Eichhornii with respect to these 

 families. 



With the general structure of A. Eichhornii I am not now 

 particularly concerned. The spumaceous appearance which 

 both the young (fig. 7) and old individuals (fig. 6) present seems 

 to be due to vacuolation, and not to the presence of cells, ac- 

 cording to the common acceptation of this term. Kolliker and 

 most others who have studied this species are of the same 

 opinion; but Prof. Clark, of Boston, has lately affirmed that 

 these vacuoles are cells, because they have a cell-wall and alter- 

 nate regularly with the tentacula (Annals, vol. xiv. p. 394). 

 However, the presence of a wall around a sarcodal aqueous 

 space, even with vibrating granules in it, does not, in the gene- 

 rally received meaning of the word, constitute a " cell." There 

 should also be a nucleus, at one time or other at least, in most 

 of such spaces, and they should at least also be of similar average 

 size, form, &c, before they can be viewed as cells of an organized 

 structure ; while all this is reversed in the vacuoles of A, 

 Eichhornii, which seem to me more to resemble, in accidental 

 form and size, the fragmentary state of a veined or brecciated 

 rock than those produced by the constant and immutable law 

 which presides over the normal development of an organized 

 cellular structure. 



How this vacuolation is produced, and to what use it is sub- 

 servient, has not been explained ; but its accidental presence in 

 the Infusoria and Algse is not uncommon. Indeed it seems 

 frequently to occur in the former from want of activity in the 

 contracting vesicle — that is, after injury of the Infusorium or to- 

 wards death. But in other instances, as in the first-formed cells 

 in the germinating nucule of Chara, a similar vacuolation seems 



