PLATE I 



MICROPHOTOGRAPHS OF A ROTIFER 



PhUodina gregaria, sp. n. 



FIGURE 1. Portion of the field of the microscope, crowded with the Rotifers, under 

 a low power. These examples were brought by Priestley from a lake in the 

 west. They were frozen solid when brought in. As soon as they were thawed 

 some were transferred by a pipette to a slide and photographed. They were 

 not narcotised, and were beginning to stretch themselves and creep about, so 

 the exposure had to be very short. Many of them have moved and are blurred 

 in the photograph. 



FIGURE 2. One of the Rotifers feeding. It is under the influence ot Eucaine, 

 but its form has been little affected by it, and is nearly normal. The dark 

 column in front of the head is formed of an accumulation of minute particles 

 which have been swept towards the mouth by the cilia of the discs. The 

 little clouds of particles on each side of the neck are those which have been 

 rejected by the selectors in the gullet, while those chosen for food have passed 

 down to the jaws. 



FIGURE 3. Side view of an extremely large example. It has been narcotised and 

 the constrictions bounding the turgid central trunk have been much deepened 

 by the influence of the Eucaine on the muscles. (Photograph by Mawson.) 



FIGURE 4. A Rotifer under slight pressure, to show some of the internal organs 

 and the well-grown young. The dark central tract was coloured deep red, 

 and the eyes, being also red, show more conspicuously than in life. 



