68 BRITISH FKESHWATEB HELIOZOA. 



they frequently possess ; and their insertion on a 

 'central grain,' which would then represent the 

 blepharoplast pure and simple of a flagellate. On 

 this view the pseudopodia of the Heliozoa would appear 

 to be structures quite different in nature from the 

 similarly-named organs of Lobosa." 



" On the other hand the Heliozoa also show affinities 

 towards forms classed among the Reticulosa or ' Pro- 

 teomyxa,' as already noted in the case of Giliophrys 

 and Pseudospora. Przesmycki has described a species, 

 Endophrys rotatorimn, parasitic in Rotifera, which he 

 considers as a connectino'-link between Niuip.aria and 

 Vampyrella. The exact systematic position of such 

 genera must be considered at present an open 

 question." 



The species TJhnorplia mutans having been recently 

 recorded in Great Britain and being one of the most 

 interesting of the flagellated type, a description of it 

 with figures is added. 



Dimorpha mutans Grruber. 

 (Text-fig. 195.) 



Diinorpha inuianx 



Getjber Zeitschr. wiss. Zool. XXXVI, 1881, p. 445, pi. xxix. 



Blochmann Biol. Oentralbl. XIV, 1874, p. 197, f. 2. 



ScHOUTBDEN Arch. Protistenk. IX, 1907, p. 108, f. 1. 

 Dimorpha nvtans (sic). 



MiNOHiN Introd. Stud. Protozoa, 1912, p. 248. 

 Actinophrys ciliatum 



Nelson English Mechanic, 27th Octr. 1916, p. 273, fig. 



Body small, shape varying from spherical to ovoid ; 

 envelope smooth, membranous, pellucid; plasma pale 

 blue in colour, containing pale green or yellow coloured 

 granules, with a clear marginal zone usually present ; 

 nucleus single, placed eccentrically, containing a single 

 hemispherical nucleolus; centrosome placed eccentri- 

 cally, from Avhich two flagella originate ; pseudopodia 

 long when fully extended, straight, tenuous, gi-anuli- 

 ferous, retractile, sometimes absent, each containing a 



