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 



FIG. 249. Dorsal view of Echiniscus 

 testudo, C. Sch., x 200, showing the 

 four segments 1, 2, 3, 4. (From 

 Doyere.) 



FIG. 250. Cast-off cuticle of 

 Macrobiotus tetradactylus, 

 Gr., x about 150, contain- 

 ing four eggs in which the 

 boring apparatus of the em- 

 bryo can be distinguished. 

 (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 



