1897] MICROSCOPICAL JOURNAL. 189 



ulong the decayed portions of the weed from which the 

 chlorophyll had departed. I was fortunate enough to 

 find in Mr. Stubbins' gathering two of the frustules of 

 this s[)ecies in the interesting state of 'conjugation,' 

 although too much attached to the weed to admit of being- 

 separated and mounted without injury to the specimen. 



Coming to the water of the 'Wishing Well' at Roche 

 Abbey, a dipping from which brought me by my \vif«- 

 some two years ago was found to contain an almost pure 

 gathering of the by no means common filamentous Dia- 

 tom Odontidium mesodon (W. Sm.), I was not a little 

 pleased on this ray first personal visit to find floating iu 

 the depths of the cool clear well water, a brown silk- 

 worm-silk-like and perfectly pure mass of this interest- 

 ing alga. After so successful a second lind of this par- 

 ticular diatom, which I may say I have never met with 

 in so pure and healthy a condition in any other of the 

 numerous waters which I have examined in various parts 

 of South Yorkshire, the 'Wishing Well' at Roche Abbey 

 ought certainly to be noted by Yorkshire naturalists as 

 a place to be visited by the lovers of freshwater algae in 

 their search for "gems." 



Proceeding to the Lake close to the Abbey ruins, it 

 was but a few minutes before I detected upon the surface 

 of this picturesque water a small piece (about an inch 

 s(iuare) of that peculiar-looking yellowish-brown scum 

 which to an experienced eye is a certain indication of a 

 'good find' of Diatomaceae. Upon examination under the 

 microscope the gathering, of which, needless to say, I 

 very quickly secured a tube, proved to be in many 

 respects similar to an extremely fertile one I made some 

 three years ago from the lake at Thoresby. Its special 

 teatui-e was its richness in unusually large frustules, .()()]" 

 in length, of Pleurosigma attenuatum, which, after care- 

 ful cleaning and boiling in nitric acid, give a brilliant 

 opal iridescence of great beauty under dark ground illu- 



