14 BRITISH FRESHWATER RHIZOPODA. 
9. Arcella catinus Penard. 
(Figs. 162 and 163.) 
Arcella vulgaris ae 
LErpy (pars) Freshw. Rhiz. N. Amer. (1879), p. 171, pl. xxviii, 
ff. 6, 7. 
Arcella catinus 
PENARD in Mém. Soc. Genéve, XX XI (1890), pp. 154-155, pl. v, £. 87. 
LAGERHEIM in Geol. Foren. Stockholm Férh. XXIII (1901), p. 507. 
Brown in Ann. Scott. Nat. Hist. 1911, p. 228; in Naturalist, 1912, 
p. 180; in Scott. Natur. 1913, pp. 186, 206. 
Waites & Penarp in Proc. R. Irish Acad. XXXI, uxv (1911), 
pp. 14, 20. 
WAILEs in Scott. Natur. 1912, p. 60. 
PLayFarr in Proc. Linn. Soc. N. 8. Wales, XLII, 4 (1918), p. 640, 
pl. xxxiv, f. 12. 
Arcella artocrea Par 
PENARD Faune Rhiz. Léman (1902), pp. 404-406, 5 figs. ; Sarcodinés 
in Cat. Invert. Suisse (1905), p. 80. (Non Arcella artocrea Leidy, 
1879.) : 
Arcella vulgaris var. compressa 
Casu Brit. Freshw. Rhiz. I. (1905), pp. 138-139, £. 28. 
Waites in Jrn. Linn. Soc., Zool. XXXII (1912), pp. 128, 131. 
Fia. 162.—Arcella catinus. 1, upper view; 2, oral view; 3, side view 
in outline. x 280. 4, Usual appearance of the surface of the test; 
5, part of the test near the aperture, with two pores. x 1000. 
(After Penard.) 
This is the same as A. vulgaris var. compressa Cash 
described in Vol. I; it may we think be legitimately 
considered an autonomous species. In the British 
