NOTES. 417 



Not to be confounded with these chlorophyll-bodies of the Protozoa 

 are certain peculiar green or olive-green discs of colouring matter 

 which occur in many Monadinre. as for example in Chnmiuliiia, Chilo- 

 wonas, Parameriuni, I'rella viregfent, Miillomonas Plteslii, kc. 



Spongilla tlridis (Sorby, Quart. Journ. Mic. Sci. 1875, vol. xv. 

 p. 47.) 



Ccelenterata : Hydra riridis. 



Platyelmia : Vortex riridi-g. 



An undescribed marine Planarian, according to Geddes. It is 

 stated that this creature decomposes carbonic acid ; no exact report, 

 however, has as yet been given, so that it is not possible to decide 

 whether this statement rests on experiment or is only inferred from 

 observations, which alone prove nothing. 



Gephyrea: Bontllia nridii (Rolando). Schenk says that the green 

 colouring matter of this worm is true chlorophyll. Sorby, however, 

 (Quart. Journ. Mic. Sci. 1875, Iviii. p. 166), after a very careful in- 

 vestigation, proves that this matter is quite distinct from chlorophyll. 



Leydig has lately propounded the hypothesis that chlorophyll may 

 occur even in insects. He founds it on the observation that the vivid 

 green of various beetles, orthoptera, &c., changes towards autumn in 

 the same way as the leaves of trees do. I regret that I cannot agree 

 with him on this point ; no such conclusion can be derived, in my 

 opinion, from the observed phenomena. The view that insects can 

 themselves elaborate chlorophyll cannot be supported by any argument, 

 and it is equally improbable that chlorophyll, as such, can be stored up 

 from the food in the circulating system of an insect, and then deposited 

 in the skin without being wholly altered ; but even if after this process 

 it could preserve its green colour and other original properties it must 

 certainly have lost the characteristic property of chlorophyll, namelv, 

 that of decomposing carbonic acid under the influence of light. 



Xote 18, page 76. Foreign bodies occur by no means rarelv as inte- 

 gral constituents of the tissue of animal organisms. Irrespective even 

 of those cases in which parasites become normal (i.e . constantly present), 

 constituents of certain portions of the body in every individual of a 

 species as for instance the Nematoda living in the foot of certain naked 

 mollusca there are numerous other examples. Among the Ccelenterata 

 there are, besides Sphenopus, various other genera which take up grains 

 of sand directly into their skin for instance, all the Zoanthime (Zoan- 

 thiis, PalijtJioa^&iC.) whereby it acquires the firmness it would otherwise 

 lack. The sponges often have the habit of including foreign siliceous 

 particles, the calcareous shells of Polythalamia, fragments of corals and 

 of the shells of molluscs, or merely sand, in their horny fibres ; sucL 

 foreign bodies occur in by far the larger number of keratose sponges. 

 That the siliceous spiculae are in these cases very often merely foreign 

 bodies is proved by the circumstance that they are found without excep- 



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