532 Transactions ofilie Society. 



The collars are of course not seen in these circumstances, as 

 they require a high power to observe them properly, but after 

 having been seen and studied under a 1/16 they are easily recog- 

 nized with a 1/4 in. or even a 2/3 under favourable circumstances 

 of illumination. 1'he mucilaginous zoocytium can only be seen 

 with difficulty owing to its extreme transparency and freedom 

 from foreign particles, and is best distinguished under black-ground 

 illumination with a low power. 



The shape of the colonies is usually more rounded than that 

 of the specimen from which Mr. Thomas's drawing was taken, 

 sometimes approaching a spherical form, but always presenting 

 indications of having been attached to some other body. They 

 probably grow on the stems of rushes, &c., but attached so slightly 

 as to be easily displaced when the water is agitated by dipping a 

 bottle, mouth downwards, amongst the rushes, moving it about 

 a little and then suddenly reversing it, taking care not to stir up 

 the mud from the bottom of the pond. 



