DACTYLOSPH^RIUM 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 Amcebse. 



Dimensions: Diameter of body (without pseudo- 

 podia) 6-12 /x. 



Various localities in Cheshire. Shelf, West York- 

 shire (G. 8. West).. Chipperfield, Herts (A. Earland). 



The genus Dactylosphserium was established by 

 Hertwig and Lesser to receive the organism named by 

 them Dactylospli&riwn vitreum. One form of this 

 appeared to be closely allied to, if not identical with, 

 forms of Mastigamceba 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 

 Dactylosphaerium polypodium, is the same organism as 

 Amoeba polypodia Max Sch. and F. E. Sch., and also 

 Dactylosphd&riitm vitreum Hertw. & Less., t. ii, f. IA 

 (the yellow form), whilst Dactylosphserium vitreum 

 Hertw. & Less., t. ii, f. IB (the green form) referred to 

 in the preceding pages, although much like some forms 

 of Mastigamceba aspera, is a distinct species to which 

 the name D. vitreum should be restricted. 



Lanessan, in ' Traite de ZooL, Protozoaires ' (1882), 

 distinguishes between Dactylosplixrium polypodium Max 

 Sch. sp,, and D. vitrsenm Hertw. & Less., indicating 

 characters for the latter which are strictly those of 

 Hertwig and Lesser's f. IB, and likewise consistent 

 with what we have observed in Mastigamceba aspera. 



Genus 3. MASTIGAMCEBA F. E. Schulze, 1875. 



Mastigamceba F. E. SCHULZE in Arch. f. niikr. Anat. XI 

 (1875), p. 583. 



Animal amoeboid in structure and habit; during 

 progression elongated, elliptic or ovoid ; the body 



