230 PROFESSOR E. RAY LANK.ESTER. 



wigs confirmed tlie observations of Cienkowsky as to the 

 independent nature of the Radiolarian yellow corpucles, 

 and held them to be parasitic. They also demonstrated that 

 the yellow corpuscles of Anthozoa had the structure and 

 properties of unicellular Algse, and were inclined to regard 

 them also as parasitic. 



The term '' symbiosis," introduced I believe originally to 

 express the relation of the green algal gonidia of Lichens 

 and the associated colourless Inophyte, has been recently 

 extended with great eftect to include the relationship of the 

 Radiolarians to their yellow cells, and also of Anthozoa to 

 tlu'ir yellow cells. 



Whilst there appears to be very nearly sufficient ground 

 for accepting the conclusion thus formulated in regard to 

 the Radiolarians and the Anthozoa, I shall endeavour to 

 show in the following pages that there is no evidence to 

 justify the extension of the doctrine of symbiosis to Spon- 

 gilla and Hydra, as advocated by Professor Semper and Dr. 

 Brandt. It appears to me, on the contrary, that an examina- 

 tion of the green-coloured corpuscles of Spongilla and 

 Hydra demonstrates those corpuscles to be similar in nature 

 to the " chlorophyll bodies " of green plants, and that there 

 is no more reason to regard them as symbiotic Algse than 

 tliere is to regard the green corpuscles in the leaf of a butter- 

 cup as such. The results of my examination of the green 

 corpuscles of Spongilla and Hydra, which have been made 

 at intervals during the past seven years, are given below. 

 I have already in this Journal (vol, xiv, p. 400, 1874) pub- 

 lished a note relative to the chlorophyll-corpuscles of 

 Spongilla. It is, perhaps, worth pointing out, that in advo- 

 cating the view that what I venture to consider as a normal 

 product of the living activity of animal cells is in reality a 

 parasite. Dr. Brandt is exactly in the converse position to 

 that occupied by Dr. Gaule, of Leipzig, whose opinion that 

 the parasitic Drepanidium phase of a Gregarina is a normal 

 product of the living activity of the blood-corpuscles and 

 other cells of the Frog, I controverted in the last number of 

 this Journal. 



Hatiire of chlorophyll. — The green colouring matter 

 which gives its characteristic tint to foliage is not a pure 

 chemical substance, but a somewhat variable mixture of 

 coloured substances, none of which have yet been properly 

 isolated and characterised by the chemist. Hence there is 

 no little difficulty encountered when we attempt to definitely 

 and satisffictorily identify the green-coloured substances 

 which appear in lower plants and in some animals with the 



