10 Mr. H. J. Carter on the " Collar " 



Clark's figures of tlic sponge-cell of Leiicosohnia hotryoides, it 

 is figured and deserlLed in his Codosiga jndcherrima (L c. p. 10, 

 pi. 9. [pi. 5, ' Annals,' 1868, vol. i.] figs. 8, 9, 25, 27, &c.). 



Further, it should Le stated that both the cell and its ap- 

 pendages are all polymorphic, or, at all events, the latter and 

 non-granular portions of the protoplasm ; so that, -while the 

 appendages may assume an infinitude of shapes and trans- 

 fonnations, the globularity of the cell for the most part remains 

 stationary. (For a description of the different forms of the 

 sponge-cell assumed imder polymorphism, and figured in the 

 illustrations, see infra^ " Explanation of the Plates," figs. 

 13-31, inclusively.) 



How the crude fragments of food are inti-oduced into the 

 sponge-cell is still so far questionable, that, as yet, it has only 

 been inferred. 



In the ' Annals ' for July 1857 (vol. xx. p. 29, pi. 1. fig. 10) 

 I described and figured what appeared to me to be the process 

 in a sponge-cell of Sj)ong{lla attached by a pseudopod to the 

 watch-glass, similar to that which I have seen twice, and 

 figured, in Grantia compressa (PI. II. figs. |20, 21) ; and there 

 (that is, as represented in the figure /. c. 10), the particles 

 seemed to be hurled back upon the cell by the cilium, described 

 in my own words at the time as " caught up (by apparently 

 adhering to it, or by a process thrown out by it, as in Actino- 

 jplirys sol {h)) and rapidly passed into its interior." 



Eespecting these observations, Prof. James-Clark states 

 {I. c. p. 1), — " Strangely enough, though, as it seems to me 

 now, he [Carter] does not look ujDon the intussusception 

 of the particles as a genuine process of swallowing, like that 

 which obtains among the ciliated Infusoria." '' It is plain, 

 therefore, that he does not believe that the ' sponge-cells' are 

 endowed with a mouth ; and moreover, if I am not mistaken, 

 he attributes to any part of the * cell ' the faculty of engulfing 

 food." 



Now here is the only point at issue between us ; and on this 

 depends whether we shall regard the sponge-cells as '•' Infu- 

 soria fiagcllata," after Prof. James-Clark's view, or as Rhizo- 

 poda (like Aviaha) after my own and tliat of others. 



It should be understood, however, that by any part of the 

 sponge-cell " engulfing food " I mean any pseudopodial pro- 

 longation or exserted process of the protoplasm ; tor it is not 

 improbable that in the I\hizi>poda the surface-layer does not 

 cover the j)scudoj)odiu)u, but, by its elasticity and yielding 

 nature, allows the transparent ami jn-ehensile nuiterial of the 

 interior to be protruded for the capture of food l^c., and then 

 withdrawn ^yithiu the rent, which aftenviuxls closes over it ; 



