ENTOZOA. 151 



is indicated at a. The alimentary canal is seen run- 

 ing down the body ; and two ova exist, one on each 

 side of it, these being often recognizable by the ex- 

 istence of the eyes and jaws. At the end of the body 

 are two lateral processes, and a tail-like piece, which 

 can be withdrawn or protruded and is furnished with 

 two moveable portions or toes. 



Pterodina pat'ina (PL XI. fig. 3). This species has 

 a shell or carapace on the back, a two-lobed rotatory 

 organ, two eyes, and a slender wrinkled tail ciliated 

 at the extremity. The curved alimentary canal, and 

 the two strong muscles inclined at an angle, are easily 

 distinguishable. 



Flosculdria orndta (PI. XI. fig. 4) is a very beauti- 

 ful member of the Rotatoria, and is found adhering 

 to Conferva and other water-plants. The body is 

 club-shaped, and contained in a transparent tube, 

 the ringed narrower portion being fixed to its base. 

 The rotatory organ is divided into five or six lobes, 

 furnished with long, slender, radiating tentacular 

 filaments ; these are not vibratile like ordinary cilia, 

 but can be slowly moved. In the contracted state, 

 the filaments form a pencil-like bundle. 



Examination, fyc. The Rotatoria are best examined 

 in the living state, the drop of water in which they 

 are viewed being very small, so that their movements 

 may be impeded ; and while they are struggling to 

 escape, the various parts of the body will come into 

 view. Their preservation has been attempted by 

 drying on a slide ; but when dead they become so 

 contracted and altered, that it is difficult to make out 

 their structure. Should the observer wish to record 

 any observations on their reproduction or habits, it 

 will be well to preserve a specimen of the jaws and 

 teeth, as the species might be with certainty identi- 

 fied by careful examination of their minute struc- 

 ture. 



ENTOZOA (eVros, within, Jwov, animal). This class 



