AMOEBA, THE FORAMINIFERA 23 



The large free-living amoebae are identified chiefly by 

 the following characters: (a) type of pseudopodia and the 

 appearance of these when the animal is crawling freely, (b) 

 the shape of the nucleus, (c) presence or absence of ecto- 

 plasmic ridges, (d) character of the contained crystals. 



Make a careful drawing of an Amoeba. 



If time and material permit, study Amoeba dubia, A. 

 verrucosa, Arcella, and Dijflugia, and compare them with 

 A. proteus. Do you understand how the shells of the last 

 two genera are made, and of what service they are? 



Drawings of these forms are desirable. 



Calkins : Genera and Species of Amoeba. Trans. Fifteenth International 

 Congress on Hygiene, 1912. The Fertilization of A. proteus. Biol. 

 Bull., 13, 1907. 



Dawson, Kessler and Silberstein: Mitosis in Amoeba dubia. Biol. Bull., 

 69, 1935. 



Dellinger: Locomotion of Amoeba and Allied Forms. Jour. Exp. Zool., 

 3, 1906. 



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



Popoff: Ueber den Entwicklungscyclus von A. minuta. Arch. f. Protis- 

 tenk., 22, 1911. 



Schaeffer: Notes on the Specific and Other Characters of Amoeba Pro- 

 teus, etc. Arch. f. Protistenk., 37, 1916. 



: Taxonomy of the Amebas. Carnegie Inst., Washington, 1926. 



THE FORAMINIFERA 



With very few exceptions Foraminifera are marine and 

 provided with shells. Specimens may be obtained from 

 material scraped from wharf pilings. 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 understand the relation of the live animal to the shell. 



Make drawings of several types of shells. 



