15 



Pseudonaviculae, which I found in the Daphnia. A very 

 close examination into the development of the Gre- 

 garines has been made by Alexander 

 Frantzius.* The systematical posi- 

 tion is still somewhat doubtful ; they 

 generally are placed between the Radi- 

 olaria and Infusoria. By having opened 

 hundreds of living cock-roaches, (not 

 then having the fear of Mr. Bergh be- 

 fore me) I found thirty -three of these 

 parasitical Gregarines in their intestines. 

 Perhaps I may find in some future 

 time, an occasion for continuing the 

 examination of their development, etc., 

 which will be published separately. 

 The easiest method for getting the larger animalcules 

 swimming in this water (Crustaceans, worms, etc.) under 

 the object-glass of a microscope, is the following : You 

 fill a large-mouthed, half gallon bottle with fresh water, 

 and let it stand for half an hour. If you have caught 

 any one of these animalcules, you will see it swimming 

 around, or having attached itself to the glass ; take a 

 glass-tube, having one of its ends drawn to a point, and 

 draw the water just over the animalcule into the tube. 

 Now, close the other end of the tube with the finger, and 

 put the contents of the tube with the animalcule in a 

 watch-glass, from which it is very easy to put under the 

 microscope. The other smaller beings are generally only 

 found by chance, or in the sediment, when the water has 

 stood for some time. 



These observations were all made with water collected 

 in different parts of the city, and not from water taken 

 from the reservoirs in the Central Park. Many of the 

 mentioned beings are only of periodical appearance, and 



* Observationes quaedam de Gregarinis. Vratislavise, 1846. 



