204 Mr. H. J. Carter on the Position of the 



tlie sponge which take in this colouring-matter, and that, when 

 they are torn to pieces in this state, the carmine paint is found 

 to be in the bodies of the spongozoa. 



Further, it Avas added that it was possible to see the frag- 

 ments of carmine paint drawn in through the pores on the 

 surface of the sponge, and then, after a break in which thej 

 could not be followed, to see them enter the circular opening 

 of the ampullaceous sac, after which they again disappeared 

 for a short interval (probably during the time that the germ 

 or nutritive part of the paint was being abstracted), when 

 fragments of colouring-matter could be seen rusiiing along 

 the larger excretory canals, and finally ejected at the single 

 vent, as the particle of growing sponge under observation 

 then consisted of only one "person " (Hiickel), and therefore 

 had only one vent. 



Thus I never could follow the particles of carmine from 

 the subdermal cavities to the ampullaceous sacs, nor observe 

 the discharged particles coming out of this sac, although my 

 mpression was that they were forced out through the same 

 aperture by which they were taken in. 



The ampullaceous sac is not always spherical nor are the 

 spongozoa always grouped into this form, but may vary in 

 number from one to several placed here and there on the 

 surface of the water-cavities or canals, whereby the carmine 

 or indigo paint (for either can be used for this purpose) may 

 be found at isolated points in the sponge-substance apart from 

 the ampullaceous sacs ; so that it might be inferred that the 

 ampullaceous sacs are not, as above stated, the only parts 

 which thus take in nutriment ', but it should be remembered 

 that it is not the ampullaceous sacs but the spongozoa which 

 do this, and therefore that it is not uncommon to hnd spongo- 

 zoa isolated singly or in small groups of different sizes charged 

 with the colouring-matter. 



With reference to the passage of tlie particles of carmine 

 into the sponge through the pores of the surface and the 

 parts into which they may be subsequently received, it might 

 be stated that, so far back as 1869 ('Annals,' vol. iv. p. 191, 

 pi. vii. fig 5), I described and delineated the fact that in 

 Grayella cyathojjhora, where the pores on the surface of this 

 siliceous sponge are confined to circumscrihed pustuliform 

 areas, the area may open directly into an " excretory canal ; " 

 and in 1885 {iib. vol. xv. p. 112, pi. iv. fig. 5) such obser- 

 vations were repeated in Halichondria scahida ; while in 

 the interval, viz. in 1879, I pointed out that in Axos sjnni- 

 "poculum the pores of the surface lead directly into an excretory 

 canal through the subdermal cavities. Thus it became 



