262 The Ohio Naturalist. [Vol. V, No. 3, 



study. Until a better knowledge is obtained of their affinities 



however, it seems advisable to consider them under the genus 



Actinolophus. 



The following summarizes our present knowledge of the group 



and indicates the position of A. minutus in respect to the other 



species. 



Genus Actinolophus, Scluilze. 



1874 Actinolophus, F. E. Schulze, Arch. mikr. Anat. v. 10, p. 392. 

 ?1893 Actinosphcsridiuni, O. Zacharias, Forschungber Plon, v. 1, p. 15. 

 1896 Acti}iolophits, Schaudinn, Das Tierreich, Heliozoa, Berlin. 



Body spherical or oval, provided with a pedicle the length of 

 which is usually much greater than the diameter of the body. 

 Body generally (always?) provided with a gelatinous envelope 

 through which the fine pseudopodia are extended. Nucleus 

 excentric. contractile vacuole (?). 



The following table will serve to separate the forms: 

 A' Pseudopodia not knobbed at the extremity. 



B' Pedicle 3-4/a in diameter, marine forms, A. pedunculatus 



B" Pedicle not more than 2/x in diameter, fresh water forms, 



C Body ovoid, diameter 1S/a, length 23/*, A. pedatus 



O Body spherical, diameter 12/x .4. minutus 



A' Pseudopodia knobbed at extremity diameter SO/u., fresh 



water forms, A. capitatus 



1. A. pedunculatus, Schulze, 1874 A. p. F. E. Schulze, Arch. mikr. 

 Anat., V. 10 p. 392 f. 1-9. 1896 Schaudinn, Das Tierreich, Heliozoa, 

 Berlin, p. 11. 



Length of body, up to SO/a, length of pedicle up to 100/*, diam- 

 eter of pedicle 3-4/x. 

 Marine, Baltic Sea. 



2. A. pedatus, (Zach.) 1893 Actinosphccridinni pcdatiini, Zacharias, 

 Forschungber. Biol. Stat. Plon., v. 1 p. 15, f. 9a, 9b. 1890 ? Actinolophus 

 pedatus, Schaudinn, Das Tierreich, Heliozoa, Berlin, p. 11. 1904 ? 

 Actinosphceridiuni pedatum, (? Nuclearia caulcsccns), (? Tokophrya), Pen- 

 ard, Les Heliozoaires d'eau douce, p. 318. 



Length of body 23/a, diameter IS/x, length of pedicle 11-30/*, 

 diameter 1.7/*. Body provided with a thick gelatinous envelope 

 from which extends extremely fine and rather short pseudopodia. 

 Nucleus oval, situated in the inferior part of the body. Con- 

 tractile vesicle not known. Color pale yellow, individuals occa- 

 sionally agglomerated by their bodies into colonies. 

 Fresh water, Germany. 



Zacharias placed A. pedatus in a new genus Actinosphaeridium 

 on the basis that it differed from Actinolophus by possessing, in 

 the encysted condition, plates covering the body. Schaudinn 

 enumerates it among the doubtful species of Actinolophus, while 

 Penard refers it back to Actinosphaeridium, at the same time call- 

 ing attention to its remarkable similarity to Nuclearia and to 

 Tokophrya. 



