114 PEOF. G. S. "WEST ON FRESHWATER RHIZOPODS 



pi. 1. fig. 13. — D. elegans, Fenard, I. c. p. 140, pi. 4. figs. 4-11. — 

 D. acuminata, Wirenh. ,Yar. elegans, G. S. West, in Journ. Linn. 

 Soc., Zool. xxviii. (1901) p. 319, pi. 28. figs. 11-12. 



Hob. Ehiconicli, Sutherland. 



It seems probable that this Difflugia retains its characters 

 sufficiently well to be regarded in the light of a species. The 

 attenuated apex is always bent at a considerable angle from the 

 longitudinal axis and is invariably perforated. The size of the 

 shell is also much less than the average size of D. acuminata^ 

 Ehrenb. 



Grenus Nebela, Leidy. 



7. Nebela dentistoma, Penard, I. c. p. 162, pi. 6. figs. 98-100 ; 

 pi. 7. figs. 1-5. — G. S.Wesf, in Journ. Linn. Soc, Zool. xxviii. 

 (1901) p. 322.— N, crenulata. Cash. 



Hah. Lund's Fell, N". Yorkshire ; amongst mosses. 



Genus Htalosphenia, Stein. 



8. Htalosphenia plattstoma, sp. n. (PI. 13. figs. 3-6.) 

 E,ather ssmall ; shell ovoid in front view, with a semcircular apex 



and a widely truncate base, consisting of a colourless, transparent, 

 chitinoid membrane ; sides of shell slightly convex and mouth 

 very wide; in side view, shell narrowly ovoid, with no trace of a 

 constriction towards the apex, slightly notched at the mouth. 

 Protoplasmic body held in position by several fine strands 

 passing to the inner surface of the shell, inferior part clear, 

 superior part granular and filled with food-particles ; pseudo- 

 podia two, short and lobose ; nucleus dorsal and prominent ; 

 contractile vacuoles not observed. 



Length of shell 40-42 /i ; breadth of shell 28-32 ^i ; breadth 

 of mouth 21-26 /x ; thickness of shell 14-15 }i. 



ILab. Near Tarbert, Harris, Outer Hebrides. 



Numerous active specimens of the above species were observed 

 in a collection from a Sphagnum-hog. The small size of the 

 shell and the extremely broad mouth are features which easily 

 distinguish it. In the side view, there is no trace of a con- 

 striction towards the apex of the shell, and there is a distinct 

 line of demarcation between the lower part of the body-pro- 

 toplasm, which gives origin to the pseudopodia, and the upper 

 granular portion. 



