ALG^. 97 



of smell to be a strong animal and offensive odour. 

 A similar offensive smell is emitted by some marine 

 sponges in a state of decay." ^ 



It hardly need be urged that the final reason is an 

 inconclusive one, and that all the foregoing are based 

 upon the assumption that conjugation, and spontaneous 

 movements, are exclusively zoological phenomena, 

 which is now admitted to have been a cardinal error. 



Moor Balls. 



The first notice discoverable of the occurrence of 

 " moor-balls " in this country is that contained in the 

 Philosophical Transactions for the year 1751, when 

 they were found in Yorkshire by Mr. William Dixon. 

 " They were taken up in a fresh-water lake on a large 

 common in the East Riding of Yorkshire, about 

 twelve miles west of Hull. The lake is from one 

 hundred to two hundred acres in size, according to 

 different seasons, and empties into the Humber, which 

 is pretty salt, and has sometimes infected it a little at 

 very high tides. The water is very bright, and the 

 bottom in many places is quite covered with these 

 balls, like a pavement, at different depths. These now 

 sent were about six inches under water, and many are 

 left quite dry every summer." On this communication 

 Mr. Watson observes that the vegetable here men- 

 tioned he had never seen before ; neither had he been 

 able to find it described in any of the botanical writers 

 he had consulted. The matter of which it is com- 

 posed is that of a Conferva, and should therefore 



• A. IT. Hassall, "Notices of Fresh Water Confervx," in Annals 

 and Mag. Xa(. Hist. (Dec, 1842), vol. x. p. 336. 



II 



