COLLECTION OF BDELLOID AND OTHER ROTIFERA. 223 



times before the stock is fit for examination. I have also on 

 some occasions obtained Bdelloida by washing dead leaves, and 

 even from tufts of the common Thrift. I have no doubt that in 

 wet weather and in places where disturbance of the surface soil 

 is infrequent, Bdelloid Rotifera, and especially young individuals, 

 creep about more freely over the ground than has yet been sus- 

 pected. Moss therefore, although the most convenient for the 

 purpose of the student, is not to be regarded as the only habitat 

 of those Bdelloid Rotifera which live away from pools and ditches. 

 In this connection I may mention some very curious habitats 

 which have been brought to my notice. Some years ago Mr. 

 Paulson handed me some specimens of a Lichen, Parmelia 

 revoluta concentrica, which has the abnormal habit of growing 

 concentrically all round some suitable loose core and thus pro- 

 ducing an egg-shaped or spherical ball which is blown hither 

 and thither by the wind on the open downs. In examining 

 some examples collected on the South Downs, Mr. Paulson had 

 discovered some Bdelloid Rotifera sheltering within the inner 

 recesses. These rotifers proved to belong to the species Macro- 

 trachela nana, a form usually met with in ground-mosses. At 

 a later date I received from Mr. Harring a tube of soft fragments 

 of rotten wood in which rotifers had been found by one of his 

 friends. On first examination I was unable to find anything 

 alive except some eel-worms, but I kept the material moist, and 

 some six months later a second examination revealed numerous 

 examples of the same species, Macrotrachela nana, which had 

 been found in Mr. Paulson's specimens of Lichen. These two 

 instances give ample proof of the potential adaptivity of the 

 moss-dwelling Bdelloida. 



Again, it will be remembered that Mr. Scourfield made re- 

 cently some investigations as to the inhabitants of certain small 

 collections of water among the exposed roots of trees, and that 

 in the small receptacles formed by the natural twistings, etc., 

 of the main roots he discovered a water- flea previously unknown. 

 He also found numerous Bdelloid Rotifera, which I was able to 

 identify as the rare Habrotrocha hidens (Gosse), and this species 

 occurred dominantly in two different gatherings. 



I come now to the after-treatment of the rotifers selected by 



