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NATURE AND AFFINITIES OF THE SPONGES. 151reported that in all the sponges examined by him he had never found anytrace of a membrane or true cell-membrane on the cells, and that thereforeall sponge structures were composed of naked cells or " gymnocytodes."indicated by Mr. Carter, this sporidular interpretation of the reproductivephenomena advocated by Professor Haeckel was in itself completely subversiveof the theory he attempted to substantiate, and, as the very essenceand starting-point of which, the existence of true and normally fecundatedova, represents an indispensable condition for the evolution of the twoprimitive germinal layers having the significance of an ectoderm and endodermin 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 ofthe sponges are to be sought.Practically following up this clue, Mr. Carter, in the ' Annals ' for Julyof the year 1871, produced a still more important contribution towards theelucidation of the structure and affinities of the sponges. On this occasionhe announced that by renewed investigations, with increased magnifyingpower, he was enabled to entirely confirm Professor Clark's discoveriesconcerning the peculiar collar-like structures possessed by the monoflagellatesponge-cells, and stated that it is out of such collared monoflagellateelements that sponge organisms are more essentially constructed.While the material supplying Mr. Carter with this important confirmatoryevidence was chiefly derived from the calcareous type Grantia compressa,other species, such as Grantia (Sycon) ciliata, Leticonia nivea, andClathrina stilpJmrea, were found to yield substantially parallel testimony.Those elements of Spongilla described by himself, in the year 1859, asflagellate cells with ear-like or spine-like points, were also now recognizedas indicating the same fundamental structural form in the fresh-waterspecies. On one point only did Mr. Carter dissent essentially from theviews of Professor Clark, namely, with reference to the mode of foodinception.While the last-named author attributed to the collar-bearingsponge-cells, and also to the independent collared flagellate types Codosigaand Salpingceca, the possession of a distinct mouth not actually discerned,but supposed to be situated within the collar, close to the base of theflagellum Mr. Carter was inclined, in consequence of the exceedingly variableor polymorphic properties of these sponge-cells, to infer that theyengulfed food at any point of their periphery after the manner of amoebae.With respect to the highly conspicuous polymorphic features of theseessential sponge-cells, he further considered that they were to be regardedrather as forms intermediate between Rhizopoda and Infusoria-Flagellatathan as typical Infusoria as interpreted by Professor Clark ; preferentially,perhaps, they were to be accepted as a distinct and independent Protozoicgroup, whose component units or individuals might be appropriately designatedsponge-animals or Spongozoa.Before the close of the same year, 1871, additional but unfortunately forAs