THE FOBAMINIFERA. 5 



5. Food materials in process of digestion are readily seen. 

 Of what do they consist? They are contained in gastric vacu- 

 oles. By careful watching, it is often possible to observe the man- 

 ner in which food is ingested and the manner in which the undi- 

 gested matter is egested. 



Make a careful drawing of an Amoeba. 



AmoebaB of various kinds represent in many respects the 

 simplest type of protozoan, and are therefore placed in the first 

 class of these animals, the Sarcodina. The individuals of this 

 class all possess pseudopodia, but many are quite unlike those of 

 Amoeba. Look over the figures of various Rhizopoda. 



If time and material permit, study Amoeba verrucosa, Arcella, 

 and Difflugia, and compare them with Amoeba proteus. Do you 

 understand how the shells of the last two genera are made, and 

 of what service they are? Why are not shells good for all forms? 



Drawings of these forms are desirable. 



Calkins: The Fertilization of A. proteus. Biol. Bui., 13, 1907. 

 Bellinger : Locomotion of Amoeba and Allied Forms. Jour. Ex. Zool., 3, 1906. 

 Metcalf : Amoeba Studies. Jour. Ex. Zool., 9, 1910. 

 Mast: Reactions in Amoeba to Light. Jour. Ex. Zool., 9, 1910. 

 Popoff: Ueber den Entwicklungs cyclus von A. minuta. Arch. f. Protist., 

 22, 1911. 



THE FORAMINIFERA. 



With very few exceptions Foraminif era are marine and pro- 

 vided with shells. Empty shells from deep-sea dredgings or from 

 the sand beaches of such islands as the Bermudas may be had 

 for study. Examine them with a low power by reflected light. 



1. Carefully examine various shells, compare them with each 

 other and with figures. Notice the great variety in size and 

 shape and determine how the chambers must have been added 

 during growth. 



2. Observe a single opening in a shell, and determine whether 

 the general surface has any finer perforations. Be sure to under- 

 stand the relation of the live animal to the shell. 



Make drawings of several types of shells. 



Farmer: Foraminif era, pp. 133-139, Lankester's Treatise. 

 Flint: Recent Foraminif era. Rep. U. S. Nat. Mus., 1897. 



