28 VIGNETTES FROM INVISIBLE LIFE. 



contrast between its dwelling and that of its near 

 relation M. ring ens. Without going into details of 

 structure, one observes that it has only a two-lobed 

 trochal disc, or crown (which, however, is very 

 beautiful), and that, although furnished with a cup- 



FIG. 5. Limnias ceratophylli. 



like organ, or pug-mill, yet it does not make bricks 

 like M. ring em : this cup-organ only secreting a 

 gelatinous fluid, with which the creature invests 

 itself, and on which it drops or throws pellets of 

 mud or rather excrement. These, sticking to the 

 viscid secretion, gradually, and without any sym- 

 metry, form a covering or refuge. So that while the 



