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Notes on a New Hydroid Polyp. 



By F. A. Parsons, F.R.M.S. 



(Bead January 2Zrd, 1885.) 



PLATE VI. 



Before describing the curious little polyp to which I wish to 

 draw your attention this evening, I will give a short account of 

 'its discovery. 



At the excursion to the gardens of the Royal Botanic Society 

 of London, on the 19th of April last, I took a gathering from a 

 tank in the house for Medicinal and Economic plants. On an 

 iron pipe in this tank there was growing some fresh-water sponge, 

 I obtained a piece of this which I placed in the bottle containing 

 my collection. 



I am in the habit of keeping the gatherings made during ex- 

 cursions as long as circumstances will permit, and this practice I 

 venture to recommend members generally to follow, as it frequently 

 happens that' many interesting objects make their appearance, after 

 a time, that would be lost if the gatherings were thrown away soon 

 after they were made. The discovery of this polyp is a case in 

 point. 



The sponge I have alluded to went the way of all sponges, and 

 nothing but its skeleton remained. This cohered, partly from the 

 way in which the spicules were matted together, and partly by 

 reason of a film of rust which had adhered to the side of the 

 sponge and by which it had been cemented to the pipe. 



Some weeks after the excursion I happened to look at the con- 

 tents of the bottle, and 'on the rusty side of the sponge skeleton 

 I saw what at first appeared to me to be a polyzoon, but so different 

 from anything I had ever seen that I was at once induced to ex- 

 amine it more closely with a pocket-lens, when the seemino- 

 resemblance vanished. I should perhaps explain that the fancied 

 similitude arose from the fact that there were a number of these 

 polyps in close proximity to each other. I took an early oppor- 



Journ. Q. M. C, Series II., No. 12. l 



