NATURE AND AFFINITIES OF THE SPONGES. 151 



reported that in all the sponges examined by him he had never found any 

 trace of a membrane or true cell-membrane on the cells, and that therefore 

 all sponge structures were composed of naked cells or " gymnocytodes." As 

 indicated by Mr. Carter, this sporidular interpretation of the reproductive 

 phenomena advocated by Professor Haeckel was in itself completely sub- 

 versive of the theory he attempted to substantiate, and, as the very essence 

 and starting-point of which, the existence of true and normally fecundated 

 ova, represents an indispensable condition for the evolution of the two 

 primitive germinal layers having the significance of an ectoderm and endo- 

 derm in the ordinary and restricted acceptation of the terms. Finally, Mr. 

 Carter directed attention to the recent discoveries of Professor H. James- 

 Clark as indicative probably of the true direction in which the affinities of 

 the sponges are to be sought. 



Practically following up this clue, Mr. Carter, in the ' Annals ' for July 

 of the year 1871, produced a still more important contribution towards the 

 elucidation of the structure and affinities of the sponges. On this occasion 

 he announced that by renewed investigations, with increased magnifying 

 power, he was enabled to entirely confirm Professor Clark's discoveries 

 concerning the peculiar collar-like structures possessed by the mono- 

 flagellate sponge-cells, and stated that it is out of such collared mono- 

 flagellate elements that sponge organisms are more essentially constructed. 

 While the material supplying Mr. Carter with this important confirmatory 

 evidence was chiefly derived from the calcareous type Grantia com- 

 pressa, other species, such as Grantia (Sycon) ciliata, Leticonia nivea, and 

 Clathrina stilpJmrea, were found to yield substantially parallel testimony. 

 Those elements of Spongilla described by himself, in the year 1859, as 

 flagellate cells with ear-like or spine-like points, were also now recognized 

 as indicating the same fundamental structural form in the fresh-water 

 species. On one point only did Mr. Carter dissent essentially from the 

 views of Professor Clark, namely, with reference to the mode of food- 

 inception. While the last-named author attributed to the collar-bearing 

 sponge-cells, and also to the independent collared flagellate types Codosiga 

 and Salpingceca, the possession of a distinct mouth not actually discerned, 

 but supposed to be situated within the collar, close to the base of the 

 flagellum Mr. Carter was inclined, in consequence of the exceedingly vari- 

 able or polymorphic properties of these sponge-cells, to infer that they 

 engulfed food at any point of their periphery after the manner of amoebae. 

 With respect to the highly conspicuous polymorphic features of these 

 essential sponge-cells, he further considered that they were to be regarded 

 rather as forms intermediate between Rhizopoda and Infusoria-Flagellata 

 than as typical Infusoria as interpreted by Professor Clark ; preferentially, 

 perhaps, they were to be accepted as a distinct and independent Protozoic 

 group, whose component units or individuals might be appropriately desig- 

 nated sponge-animals or Spongozoa. 



Before the close of the same year, 1871, additional but unfortunately for 



