400 NOTES AND MEMORANDA. 



turien der Susswasser Algen Europas/ under the name of 

 Clathrocystis roseo-persicina, the adult form belonging to the 

 genus Clathrocystis of Henfrey. I took much pains with the 

 study of these curious organisms last year, before I was ac- 

 quainted with your memoir on Bacterium rubescetis, and I 

 had in view to publish my researches in the next part of my 

 ' Beitrage zur Biologie,' but the number has been delayed up 

 to this moment. 



" I must confess that, though I had strong suspicion of a 

 genetic connection between Mo7ias Okeni and Clathrocystis 

 roseo-persicina, both being commonly found together, yet I 

 could never find any convincing proof of it. 



" I shall put the growth you favoured me with into the 

 conditions described in your letter, and I hope to find, after 

 my return from my summer's holiday, the development of 

 the organism." 



Mr. Lankester has observed further very interesting phases 

 in the -life history of this alga, which will be described in an 

 early number of the Journal. The most remarkable are large 

 subspherical bodies, reaching as much as 200th inch in dia- 

 meter. These are entirely homogeneous in structure, and 

 deeply stained with Bacterio-purpurin. They appeared in 

 the winter months, when the growth died down to a very 

 small size. Finely granular bodies and somewhat more 

 coarsely granular bodies of the same character were also 

 found, leading by an easy transition to the spherical agglome- 

 rations of homogeneous oval plastids (zoogloea-like aggrega- 

 tions) figured in the Journal, October, 1873, from which it 

 appears probable that the large structureless bodies develop by 

 a multicentral segregation into the loosely connected aggre- 

 gations of Bacterium-like plastids. 



The Mode of Occurrence of Chlorophyll in Spongilla. — Mr. 

 H. C. Sorby is at present engaged in an examination of the 

 green colouring matter of Spongilla with the spectroscope. 

 In 1869 I made some observations of the kind (published in 

 the ' Journal of Anatomy and Physiology *), and showed by 

 spectroscopical evidence that chlorophylloid colouring matter 

 was present in this organism. Mr. Sorby informs me that 

 he has recognised in Spongilla all six of the chlorophyll- 

 constituents which he has distinguished in the higher plants 

 (see his paper on '^ Vegetable Chromatology," ' Proc. Royal 

 Society,' 1873). I have recently examined the morpho- 

 logical character of the chlorophyll of Spotigilla. I find 

 that among the amoebiform sponge-particles of a green- 

 coloured specimen of Spongilla, some are composed of naked, 

 finely molecular, colourless protoplasm, throwing out abso- 



