136 BRITISH FRESHWATER RHIZOPODA. 



Length 60-160 /x. Nuclei 6 /x in diameter. 

 Habitat. On Algge. Freshwater and marine. 



IRELAND. Near the lighthouse, Clare Island, Mayo 

 (Wailes fy Penard). 



When the test assumes a spherical form the aper- 

 ture is difficult to locate as it becomes a mere slit 

 immersed in the exuding plasma ; also the test may 

 be covered by extraneous matter (grains of sand, 

 diatoms, etc.) which adhere to it although they are 

 not incorporated with it. In these circumstances the 

 peduncle or raphe may be indistinguishable, consisting 

 as it does of a fine ribbon-like band within the test 



FIG. 156. Lieberkuehnia ivageneri, without its pseudopodia. x about 

 250. (After Penard, as L. fluvialis.) 



and lying closely to one side of it for about half its 

 length, its aperture end spreading out and forming 

 the origin of a very extensive reticulum. A portion 

 of the plasma often flows around the outside of the 

 test, more or less enveloping it with a coating from 

 which pseudopodia sometimes arise. The numerous 

 nuclei are spherical and each contains a single nucleole 

 lying at one side, shaped like the segment of a sphere, 

 so that in broad view they appear circular and placed 

 centrally in the nucleus, whilst in narrow view they 

 are nearly hemispherical and lie close to one side of 

 it. To see the nuclei it is frequently necessary to 

 crush the test and expel the pla'sma. In young indi- 

 viduals Penard has found two or three very small 

 nucleoles in each nucleus. 



