DACTYLOSPHARIUM POLYPODIUM. 69 
by their quickly-projected, mostly numerous pseudo- 
podia, but even their body-mass took an active share 
in locomotion, similar to that of Am«be. 
Dimensions: Diameter of body (without pseudo- 
podia) 6-12 p. 
Various localities in Cheshire. Shelf, West York- 
shire (G. S. West). Chipperfield, Herts (A. Harland). 
The genus Dactylospheriwm was established by 
Hertwig and Lesser to receive the organism named by 
them Dactylospheriwm vitreum. One form of this 
appeared to be closely allied to, if not identical with, 
forms of Mastigameba aspera F. E: Schulze. Mr, John 
Hopkinson has been at considerable pains recently to 
investigate the relationships of the different forms 
described by these authors, and has come to the con- 
clusion that the species which we here refer to 
Dactylospherium polypodium, is the same organism as 
Ameba polypadia Max Sch. and F. EH. Sch., and also 
Dactylospherium vitreum Hertw. & Less., t. ni, f. 1a 
(the yellow form), whilst Dactylospherium vitreum 
Hertw. & Less., t. 11, f. 1B (the green form) referred to 
in the preceding pages, although much like some forms 
of Mastigameba aspera, is a distinct species to which 
the name LD. vitreum should be restricted. 
Lanessan, in ‘ Traité de Zool., Protozoaires’ (1882), 
distinguishes between Dactylospherium polypodium Max 
Sch. sp, and D. vitrewm Hertw. & Less., indicating 
characters for the latter which are strictly those of 
Hertwig and Lesser’s f. 1s, and likewise consistent 
with what we have observed in Mastigamcaba aspera. 
Genus 3. MASTIGAMGBA F. E. Schulze, 1875. 
Mastigameba F. BE. Scuunze in Arch. f. mikr. Anat. XI 
(1875), p. 583. 
Animal amoeboid in structure and habit; during 
progression elongated, elliptic or ovoid; the body 
