HETEROPHRYS EADIA'l'A. 33 



observed ; nucleus single, placed eccentrically ; no 

 central granule observed ; pseudopodia numerous, 

 long, delicate, granuliferous ; no pulsating vesicle 

 obsex'ved. 



Diameter of body 2] ij, ; diameter of outer envelope 

 53 /x. ; length of pseudopodia 43 jjl. 



Habitat. — On vegetation {Mijriopliyllum) in ponds. 



Distribution. — England. — Bpping Forest, Essex 

 {West). . 



A'one of the observed individuals contained any 

 green algal cells. 



The pseudopodia had numei^ous relatively large 

 graniiles scattered at intervals along their length. 



Genus 5. RAPHIDIOPHRYS Archer. 



Raphidiophrys Aecher Qrt. Jrn. Micr. Sci. (n.s.) YII, 1867, 

 p. 179. 



Body enclosed in a mucilaginous envelope contain- 

 ing spicules, spindle-, awl-', or disc-shaped, which 

 normally extend outwards along the pseudopodia; 

 nucleus and endoplasm placed eccentrically. 



The identification of the species in this genus 

 largely depends on the shapes of the investing 

 spicules; this may necessitate the isolation of the 

 individual and its examination either in a dry state 

 or after treatment with sulphuric acid ; in either case 

 a high magnification is desirable. 



The following is a short description of the species 

 belonging to this genus which have not vip till now 

 been recorded from the British Isles : 



R. socialis Leidy. — Usually in large colonies in which the 

 individuals, sometimes as many as one hundred, are loosely 

 associated; spicules numerous, straight, extremely tenuous j 

 several contractile vesicles may be present; the nucleus 

 stated to be placed centrally, but as Leidy gave no drawing 

 and no subsequent record has been published this statement 

 requires corroboration. Individuals 24 ^u to 36 /x diameter of 

 body. 



3 



