1870.] RITCHIE — ON AQUARIA STUDIES. 169 



a large-sized drop of water on a slip of glass, and held it over the 

 flame of a lamp, loDg enough for the glass to be uncomfortable 

 to the fingers, with the like result. They only appeared to be a 

 little more active after their warm bath. 



The old experiment of evaporating a drop of water on a slide 

 containing Kotifers we have also tried, and, on again wetting the 

 spot, have resuscitated some of them. We have had them the 

 twenty-fifth to the thirtieth part of an inch in length ; about the 

 fiftieth part of an inch is the usual size. 



A little to the left of the Kotifer, attached to a piece of Conferva, 

 is a beautiful cluster of bell-shaped animalcules, Vorticella 

 campaindaria. They sre attached to the plant by means of a 

 stalk, which has a contractile muscle running from the base 

 to the upper end : they have a ciliated mouth. Just watch 

 that little cluster of crystal bells. They have, by means of the 

 muscle, drawn back, until they look like an irregular mass of 

 gelatine. Now they slowly move out again, as if all were guided 

 by the same will. Now they are at full stretch, with cilia 

 revolving, fishing and feeding. Again, they are all retracted with 

 a jerk. Some of them look as if they were double. Reproduction 

 is going on in these : it is elfected by fission. Bye-and-bye these will 

 separate and detach themselves, and swim about till matured, 

 when they attach themselves, to go through the same existence as 

 their progenitors. 



A smaller species, Vorticella nehiilifera, is to be found 

 attached to the bodies of some Entomosiraca, as Cijclops 

 quadrlcornis, and on Lynceus. Another species (Carchesmm 

 poli/pimnn) is also found attached to these creatures. We have a 

 specimen of Cyclops mounted as a microscopic object, having 

 Vorticella nehulifera attached to the back of the crustacean. 

 The presence of the Vorticella on the slide was accidental, as the 

 object was intended to be Volvox glohator only. It evidently got 

 in either attached in some way to some of the Coiifervce, or from 

 the water. 



The stalks in Carchcsium are not retractile ; the body, however, 

 has the power of closing up by muscular action. These we have 

 not found in nuiubors in our aquarium, but in the ponds near the 

 city they are to be met with in abundance. 



Another beautiful creature— the Blue Stentor (Stentor 

 ca^ruleus)—h'dii attached itself to a little bit of weed ; its beautiful 

 crown of cilia is expanded, and moves rapidly, creating quite a 

 YOL. 5. L Xo. 2. 



