observations 11-3-11

Yesterday I observed all of the organisms mentioned previously without any drastic changes in population sizes.  Like last week, however, I found several new organisms.  Near my Utricularia plant, I saw a pair of invertebrates, Philodina sp., feeding (Rainis and Russell 1996, p.188).  Like Vorticella, Philodina has a mouth lined with cilia that suck up food.  Under the microscope, however, Philodina appears to have two lateral "jaws" like a beetle that it can extend and retract.  Once again, I saw a lone Phacus triqueter, but this time I also identified another species, Phacus longicaudus (Forest 1954, p.294 fig. 414).  As the name implies, the distinguishing characteristic of  P. longicaudus is its tail, which is about as long as its body.  This week I also saw an amoeba (Amoeba sp.) in my aquarium for the first time (Lee, Hutner, and Bovee 1985, p. 161 fig.1).  When I first observed it, the amoeba was in its radiate, free-floating form, but it gradually transformed.  Here is a picture of the radiate form:

Lee, Hutner, and Bovee 1985, p. 161 fig.1