98 BRITISH FRESHWATER RHIZOPODA. 



2. Corythion pulchellum Penard. 

 (Plate XL VIII, figs. 19-22.) 



] Euglypha minima 



PERTY Kennt. kleinst. Lebensf. (1852), p. 187, pi. viii, f. 20. 

 Corythion pulchellum 



PENARD in Mem. Soc. Geneve, XXXI. i, n (1890), p. 189, pi. ix. 

 ft. 27-36; in Jahrb. nassau. Ver. Naturk. XLIII (1890), p. 72; in 

 Amer. Natur. XXY (1891), p. 1081 ; Faune Bhiz. Leman (1902), 

 pp. 532-533, 4 figs.; in Arch. Protist. II (1903), p. 272; Sarcodines in 

 Cat. Invert. Suisse (1905), p. Ill ; in Arch. Protist, IX (1909), p. 265. 



AVERINTZEFF in Trudui S.-Peterb. Obshch. XXXVI, n (1906), p. 315. 



SCHOTJTEDEN in Ann. Biol. lacustre, I (1906), p. 372. 



HEINIS in Arch. Hydrobiol. Y (1910), p. 111. 



BROWN in Ann. Scott. Nat. Hist. 1911, pp. 229, 230; in Naturalist, 

 1912, p. 112 ; in Scott. Natur. 1912, p. 181 ; 1913, pp. 208, 210. 



WAILES & PENARD in Proc. R. Irish Acad. XXXI, LXV (1911), pp. 

 15, 60, 61, 62. 



WAILES in Scott. Natur. 1912, p. 60 ; in Jrn. Linn. Soc., Zool. XXXII 



(1912), p. 126; in Naturalist, 1913, p. 147. 

 Chorythion pulchellum 



AVERINTZEFF in Zool. Anzeig. XXXI (1907), p. 311. 



Test small, hyaline, in broad view oviform, mode- 

 rately compressed, truncate at the anterior extremity ; 

 in narrow view rounded posteriorly and tapering 

 sharply towards the aperture ; transverse section oval ; 

 aperture oblique, narrowly lenticular ; plasma clear, 

 colourless, with few granules ; nucleus containing a 

 single nucleole placed posteriorly ; two or three con- 

 tractile vesicles usually present; pseudopodia unknown. 



Length 26-35 /a; breadth 1 5-2 JJL ; aperture 7- 

 10/x; by 3-4 /A in width; thickness about two thirds 

 the breadth. 



Habitat. Mosses and sphagnum. 



Never very numerous, 0. pulcliellum is widely dis- 

 tributed. The test is so transparent that it is easily 

 overlooked and the small plates of which it is formed 

 are difficult to distinguish without special preparation. 



In this species, as also in the preceding, a small 

 filament is sometimes observed situated near the aper- 

 ture; it is always comparatively short, of a tough 

 nature, and appears as if it might be used for attaching 

 the test to some object. 



