better knoion as the Coccolith. 185 



eminent naturalist had first formed, in 1858 {op. cit.), viz. that 

 it was a unicelkilar Alga, I still further became convinced of 

 this by finding- it abundantly in the alimentary canal of the 

 large Ascidian [Ascidia arachnoidea, Forbes & Hanley) which 

 is thrown ashore here duiing storms. 



deferring, then, again to Prof. Huxley's paper and accu- 

 rate illustrations of coccoliths, I observed that he came to the 

 two following conclusions, viz. : — 



(1) " That they are not independent organisms, but that 

 they stand in the same relation to the protoplasm of Bathyhius 

 as the spicula of Sponges or of Radiolaria do to the soft parts 

 of those animals ;" and (2) " that the coccospheres are from 

 the first independent structures, comparable to the wheel-like 

 spicula associated in the wall of the '■ seeds ' of S2)on<jilla^ 

 and perhaps enclosing a mass of protoplasm [of Bathyhius] 

 destined for reproductive purposes " {J. c. pp. 210 & 211). 



Now, finding the coccolith so abundant throughout the La- 

 minarian zone here that hardly any object can be examined mi- 

 croscopically without its presence in greater or smaller numbers, 

 also that in the alimentary canal of the Ascidian just men- 

 tioned it is more abundant than the frustules of Diatomaceae 

 or the remains of any other organism of this kind, while it is 

 in a more or less fragmental condition, indicative of the effect 

 of digestion, I could not help feeling still more in favour of 

 its being an organized cell. 



Hence I subjected a portion of the contents of the alimen- 

 tary canal of Ascidia arachnoidea^ in which there were many 

 entire as well as fractured coccoliths, to the following chemical 

 tests, watching at the same time their efiect, under a glass 

 cover, with the microscope. 



(1) Solution of iodine in iodide of potassium produced no vi- 

 sible alteration. (2) Acetic acid, being added in sufiicient quan- 

 tity to more than neutralize the former, caused the calcareous 

 cell of the coccolith to become dissolved, leaving a granular disk 

 of protoplasm, in the centre of which was the original oval 

 transparent area containing one or more granules, as the case 

 might be : all the granules were of a yellowish colour, both 

 in the disk and transparent area ; and as the cell became dis- 

 solved away, so the greenish tint, which is owing to the pre- 

 sence of the calcareous material, also disappeared ; but still no 

 further visible change occun-ed. (3) The sol. iodine &c. was 

 again let in (by the aid of a piece of bibulous paper which was 

 placed on the opposite side of the cover) ; but the granules &c. 

 still remained unaltered, and did not present the blue tint in- 

 dicative of starch. (4) Finally, the acetic acid was reapplied, 

 without further change ; and after the aqueous contents had 



