478 TARDIGRADA CHAP, 
case has yielded a good supply of Tardigrades otherwise so 
difficult to find. The method is to soak the heather in water 
for some hours and then thoroughly shake it, or to shake it 
gently in a rocking machine for some hours. The sediment is 
allowed to settle, and is then removed with a pipette and placed 
in a centrifugaliser. A few turns of the handle are sufficient to 
Fie. 250.—Cast-off cuticle of 
Macrobiotus tetradactylus, 
Gr., x about 150, contain- 
Fia. 249. —Dorsal view of Echiniscus ing four eggs in which the 
testudo, C. Sch., x 200, showing the boring apparatus of the em- 
four segments 1, 2, 3, 4. (From bryo can be distinguished. 
Doyere.) (From R. Greeff. ) 
concentrate at the bottom of the test-tubes a perfectly amazing 
amount of cryptozoic animal life, and amongst other forms I 
have never failed to find Tardigrades. 
Many Tardigrades are very transparent; their cells are 
large, and arranged in a beautifully symmetrical manner; and 
since those of them that live in moss, and at times undergo 
desiccation, are readily thrown into a perfectly motionless state, 
during which they may be examined at leisure, it is not sur- 
prising that these little creatures have been a favourite object 
