1897] MICROSCOPICAL JOURNAL. 189 



along the decayed portions of the weed from wliich the 

 chlorophyll had departed. I was fortunate enough 'to 

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

 this species 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 dij)ping from which brought me by my wife 

 some two years ago was found to contain an almost pure 

 gathering of the by no means common filamentous Dia- 

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

 pleased on this my first personal visit to find floating in 

 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 find 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 

 square) 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 

 feature was its richness in unusually large frustules, .001 " 

 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- 



