RECENT MEMOIRS ON FRESHWATER RHIZOPODA. 371 



from tangential to approximately radial, and often forming 

 conical heaps projecting outwardly. From the generally 

 smooth surface of the body proceed radially slender filiform 

 pseudopodia passing through the skeleton-layer; they neither 

 branch nor anastomose ; they are straight, finely pointed, 

 and mostly in length considerably exceeding the diameter of 

 the body. 



Amongst the numerous minute granules imparting a 

 cloudy appearance to the body-substance, some larger, pale, 

 shining corpuscles can mostly be distinguished irregularly 

 distributed towards the outer part of the body, but not at 

 its extreme limits. The author describes them as correspond- 

 ing in figure, size, and position to the " so-called " chloro- 

 phyll-granules of such Heliozoa as Raph. viridis and Acanth. 

 viridis. He supposed that these increased in quantity with 

 increased nutriment, and that they disappeared with long 

 fasting. 



He demonstrated the presence of a distinct nucleus in the 

 interior of the body. It strikes the observer, on account of 

 its large, strongly refractive, homogeneous and hence some- 

 Avhat shiny nucleolus (of about 0"01 mm, in diameter j, which 

 appears to be either smooth and roundish or oval, or tubercu- 

 late, or even indented. The nucleolus appears surrounded by 

 a narrow border, marked off so sharply against the surrounding 

 plasma as to give the idea of possessing an enclosing mem- 

 brane (Kernmembran). The nucleus as a whole is oval or 

 egg-shaped, more rarely globular, and has a diameter of 

 about 0'015 mm. It lies very excentric, indeed close to the 

 periphery, mostly Avith its longer axis in a radial direction. 

 Extremely rarely the author saw two nuclei. 



On seeking for a cause of the very excentric position of 

 the nucleus, the author was surprised to discover that here, 

 as well as in Acanth. viridis, according to Grenacher and 

 Greeff^s descriptions, " a skeleton is present, consisting of 

 fine spines standing radially and uniting in the centre in a 

 stellate manner/' 



In Acanth. viridis (I believe identical with A. turfacea. 

 Carter) Grenacher described in the centre of the body '* a 

 somewhat large, irregularly stellate cavity, apparently filled 

 with watery fluid.'' In the middle of this he found " a little 

 pale, roundish corpuscle, from which ran in all directions 

 radially numerous likewise pale, straight threads." Athough 

 he could not follow them, Grenacher supposed these were in 

 connection with the delicate axile threads of the pseudopodia. 

 A similar connection of " axile threads " with a similar 

 central structure Greeff thought he saw in Actinophrys sol. 



