APPENDIX 



285 



irregularly among the granellae. In some cases (Fig. 3) aggregations of 

 nuclei with an investing portion* of the protoplasm become separated from 



-r. 



FIG. 2. 



Section through the middle layer of J'srnnminn glubigfrina, Haeckel, showing the plexus of 

 tubes containing a multinucleated plasmodium. At o, a are seen some of the foreign bodies 

 (xenophya) associated with the organism ; s, s, tubes of the sterkoinarium ; g, g, tubes of the 

 granellarium. (After Schultze.) 



the plasmodium, and these break up into swarm-spores, which Schultze 

 regards as possibly gametes. 



In the family Stannomidae there are found, in addition to the tubes- 

 already mentioned, many fine skeletal fibres called the " linellae," which 

 form a plexus in the interstices of the other 

 parts of the organisms. 



In the absence of any information con- 

 cerning the early stages of development, or 

 of the character of the pseudopodia in the 

 members of this family, it is difficult to 

 assign to them their proper systematic 

 position. The Foraminiferan genus Poly- 

 trema and some of its allies liave the same 

 habit of incorporating into their substances 

 sponge spicules and other foreign bodies, and 

 they also lose at an early stage of develop- 

 ment the external evidence of the chambered 

 condition, and assume dendritic forms. 

 Moreover, in Polytrema we find, in addition 



to the calcareous skeleton, a system of are breaking up into spores, 

 horny or chitinous tubes which have some 



resemblance to the tubes of the Xenophyophoridae. In the absence of a 

 calcareous "skeleton the family differs from all the higher and more 

 differentiated families of Foraminifera, but nevertheless the affinities of 

 the family are greater \vith this class than with any other Protozoa. 



FIG. 3. 



Diagram of the granellar region- 

 of a Xenophyophorid, showing the 

 nuclei, n, n, and granellae, g, g, of 



