Mr. H.J.Carter on the Organization of Infusoria. 233 



Cliaraccjc before they pass \nto Amabte ; while the number of 

 the former being as great in the first portion of sponge which 

 issues from the capsule as in the older mass, if not more so, 

 seems not only to support this view, but also that they do not 

 all form part of the surface-layer of the canals in which cilia 

 ha^e been detected by ]\Jr. Bowerbank, for at this period thei'e 

 are no canals present. The facts above mentioned, however, are 

 o})])osed to this view ; for there is a marked difference between 

 the reptant sponge-cells produced from the ovules in the watch- 

 glass, and the monociliated ones developed from the granules, 

 both in size and appearance (/, vi) ; and although the cilium sub- 

 sequently seen in the former may have pre-existed in the ovule, 

 still, both being polymorphic, rhizojjodous cells, and, therefore, 

 when united undistiuguishable individually, the cilium might 

 belong to either, i. e. to the sponge-cell or to the incorporated 

 granule, — the latter of which may frequently be verified when 

 examining a piece of Sponyilla torn to pieces, under the micro- 

 scope (fig. 43). Whether or not, however, both possess a cilium 

 at first, the sponge-cell loses it afterwards, whatever may happen 

 to that of the supposed zoosperm, which may not become incor- 

 porated with one ; and this may be the case with the monads 

 which are produced from the rhizopodous cell of the Characese, — 

 there may be two kinds. 



-Should it be hereafter proved that the granules of the nucleus 

 thus become impregnating agents, then this mode of generation 

 may perhaps be extended through Euglena to Navicula, Closte- 

 rium, Spirogyru, QLdogonium, and Cladophora ; for in none of 

 these Algse has anything approaching to a process of generation 

 been detected beyond conjugation and the formation of the 

 spore; while, indeed, in Spirogijra mirabile (Hass.), QLdogonium, 

 and Cladophora, the si)ore is formed without conjugation. — 

 Might not the gi-anulatiou of the nucleus, &c. go on in the 

 spore ? 



In Cladophora the gonimic substance consists of nucleated 

 cells, each containing a portion of green chlorophyll-bearing 

 protoplasm, and these are arranged in the way of a pavement on 

 the inner side of the cell ; hence we must consider Cladophora a 

 composite Alga, which would then form the first step to the cell 

 of Nitella, in which the green chlorophyll-bearing cells would 

 correspond to the same kind of organisms in the cell of Clado- 

 phora ; but as the form of Nitella is more complicated, so it re- 

 quires distinct organs of reproduction for its general develop^ 

 mcnt. That the conjectured mode of generation mentioned in 

 the freshwater Rhizopoda may be the same as hi the lower Algaj, 

 and that the addition of other and distinct organs for this pur- 

 l)ose in the higher developments is a necessary sequence of their 



