THE SARCODINA 



233 



in some individuals, hence termed microspheric, the initial chamber of 

 the shell is smaller than in others, which are known as megalospheric. 

 This point will be discussed further under the reproduction. 



It may be noted that if, in this order, a species were to form no 

 shell, whether from having secondarily lost the habit or as a primi- 

 tive form which had never acquired it, then such a species would be 

 classed in the order Amcebaea Reticulosa. It is very probable that 

 many of the large marine " Proteomyxa " are allied to the true 



FIG. 94. Biloculina depressa : transverse sections of (a) the megalospheric form, 

 magnified 50 diameters, and (b) the microspheric form, magnified 90 diameters. 

 After Schlumberger, from Lister. 



Foraminifera, as forms either primitively or secondarily without a 

 test ; and Rhumbler unites the Foraminifera proper with the naked 

 forms in the section Reticulosa. 



The body-protoplasm exhibits no marked distinction of ecto- 

 plasm and endoplasm. Contractile vacuoles are present in some 

 of the fresh-water genera, but are not found in marine forms. 

 The protoplasm contains metaplastic bodies of various kinds, and 

 may become loaded with fseoal matter in the form of masses of 

 brown granules, termed by Schaudinn the " stercome " (compare also 

 Awerinzew, 281). Periodically a process of defaecation takes place, 

 whereby the protoplasm is cleared of these accumulations, often as 

 a prelude to the formation of a new chamber (Winter, 28). The 



