58 J. MURRAY ON WATER-BEARS, OR TARDIGRADA. 



often appear to be playing with these spiny balls, holding on 

 to them with the last two pairs of legs and pawing the air (in 

 this case water) in an apparently aimless and more or less 

 violent fashion, as represented in Plate 7, Fig. 1. The animals 

 are Water-bears or Tardigrada, and the spiny objects are their 

 eggs. 



They are not confined to tree moss, however, but occur equally 

 among moss from rocks and walls, streams, lake margins, and 

 peat-bogs — indeed, wherever you find moss you may find Water- 

 bears. They are also common among the mud of ponds and 

 even in the dust of gutters, where some of the first were seen. 



Method of Collecting. 



It is not enough to know the haunts of the Water-bears. If 

 we take the moss, or mud, or dust which we wish to examine for 

 Tardigrada, and put it in water, making an " infusion," we 

 are likely to find the bears ; but they may not be in sufficient 

 numbers to serve for study. 



To get them in quantity, definite methods of collecting are 

 serviceable, and I will give an account of that which I have 

 found best. It is equally available for obtaining all kinds of 

 microscopic animals which shelter in the axils of moss-leaves. 



The moss to be dealt with is put into a conical bag of bolting 

 silk of such a mesh as will allow Water-bears to pass through 

 No. 6 bolting silk, I find, answers very well). A strong stream 

 of water is then made to play upon the moss, in order to wash the 

 microscopic animals out from the axils. As the stream of water 

 passes through this coarse net, carrying Water-bears and similar 

 small objects with it, it is caught below in a much finer silk net 

 (Nos. 17 to 20 bolting silk). The fine sediment collected in this 

 net can easily be transferred to a bottle, after being sufficiently 

 concentrated. 



Methods of Observation. 



The means of observation to be adopted in order to ascertain 

 the species of Water-bears are simple and easy. 



If a drop of sediment, obtained as directed above, is placed on a 

 slide and covered by a slip, it may be examined by a low power 

 of the microscope, in order to find if bears are present. When 



