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



Clark's figures of the sponge-cell of LeiocosoJenia hotryoides^ it 

 is figured and described in his Codosiga pulcherrima (1. c. p. 10, 

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



Further, it should be 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- 

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

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

 sponge-cell assumed under polymorphism, and figured in the 

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

 13-31, inclusively.) 



How the c7-ude fragments of food are introduced 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 Spongilla attached by a pseudopod to the 

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

 figured, in Orantia convpressa (PI. II. figs. [20, 21) ; and there 

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

 seemed to be hm'led 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- 

 jphrys sol (b)) and rapidly passed into its interior." 



Respecting these observations. Prof. James-Clark states 

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

 now, he [Carter] does not look upon 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 flagellata," after Prof. James-Clark's view, or as Rhizo- 

 poda (like Amoeba) after my own and that 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 ; for it is not 

 improbable that in the Ehizopoda the surface-layer does not 

 cover the pseudopodium, but, by its elasticity and yielding 

 nature, allows the transparent and prehensile material of the 

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

 withdrawn within the rent, which afterwards closes over it ; 



