106 BRITISH FRESHWATER RHIZOPODA. 
Genus 12. HYALODISCUS Hertwig & Lesser, 1874. 
Amiha (pars) Dusarpin Infus, (1841), p. 285. 
eg Herrwic & Lesser in Arch. f. mikr. Anat. 
X (1874), Suppl. p. 49. 
Placopus F. EB. Scuutzs in Arch. f. mikr. Anat. XI (1875), 
p. 348. 
Tampyrella (pars) Kuztw in Bot. Centralbl. VIII (1881), 
p. 321. 
Body discoid, of indefinite outline, surrounded by a 
band of clear ectoplasm of varying width, with a 
reddish, frequently much vacuolated granular endo- 
plasm in which may be detected, under favourable 
conditions, an inconspicuous nucleus. Endoplasm 
similar in appearance to that of Vwinpyrella, sometimes 
projected into conical or filamentous processes. 
The band of transparent ectoplasm, completely 
enveloping the body, is distinctive of this genus, and 
separates it from the alhed Vampyrelle. 
1. Hyalodiscus rubicundus Hertwig & Lesser. 
(Plate XIII, figs: 2-11.) 
Hyalodiscus rubicundus Hertwie & Lesser in Arch. f. mikr. 
Anat. X (1874), Suppl. p. 49, t. ii, f. 5; AnLMan in 
Journ. Linn. Soc., Zool. X{II (1877), p. 267, f.2; AncHER 
in Q. J. Micr. Sci. XVII, n.s. (1877), p. 842, t. xxi, f. 16 ; 
Magar in Rend. R. Ist. Lomb. (2) X (1877), p. 321; in 
Atti Soc. Ital. XXI (1878), pp. 318, 317; and in Boll. 
Scient. I,an. 2 (1880), p. 34; Hirewcock Synops. Freshw. 
Rhiz. (1881), p. 10; LANESSAN Traité Zool., Prot. (1882), 
p. 48; BiocuMann Mikr. Thierw. Siisswass. (1886), p. 10, 
t. i, f. 5; Saccur in Boll. Scient. III, an. 10 (1888) p. 43, 
and loc, cit. an. 11 (1889), p. 68; Luvanprr in Acta Soc. 
Fauna Fenn. XTI (1894), no. 2, p. 11, and in Zool. Anzeig. 
XVII (1894), p. 209; Penarp Faune Rhiz. Léman (1902), 
p. 159, ff. 
Plakopus ruber F. EB, Scuutze in Arch. f. mikr. Anat. XL 
(1875), p. 348, t. xix, ff. 9-16; Axtman in Journ. Linn. 
Soc., Zool. XIII (1877), p. 270, f. 4; Arcuer in Q. J. 
Micr. Sci. XVII, nis. (1877), p. 349, t. xxi, ff. 23; 
Lannssan Traité Zool., Prot. (1882), p. 49. 
