ARCELLA CAT1NUS. 15 



Isles it is somewhat rare, although it is sometimes 

 numerous in the localities where it does occur. 



Cash in his description and figure has omitted the 

 pores which surround the oral aperture and are usually 

 about twelve in number. 



It is quite distinct from A. artocrea Leidy, although 

 Penard referred it to that species in his ' Faune Rhiz. 

 du Leman ' (1902) thinking it might be a European 



FIG. 163. Arcella catinus. Upper and lateral views, x 260. (After 



Cash.) 



form of it, but A. catinus in its typical form, as drawn 

 by Leidy (PI. xxviii, figs. 6 and 7) and Cash, is not 

 uncommon in America. 



3. Arcella arenaria G-reeff. 

 (Plate LVIII, figs. 4 and 5.) 



Arcella arenaria 



GREEFF in Arch. mikr. Anat. II (1866), p. 330, pi. xviii, f. 16; in 



Sitzb. Ges. Marburg, 1888, pp. 106-107. 



LAGERHEIM in Geol. Foren. Stockholm Forh. XXXIII (1901), p. 507. 

 LEVANDER in Acta Soc. Fauna Fenn. XX (1901), p. 7. 

 PENARD Faune Rhiz. Leman (1902), pp. 406-408, 3 figs. ; in Arch. 



Protist. IX (1903), p. 258 ; Sarcodines in Cat. Invert. Suisse (1905), 



pp. 79-80; in Deux exped. Antarct. fra^aises (1911), pp. 4, 5. 

 AVERINTZEFF in Trudtu S.-Peterb. Obshch. XXX VI, 11 (1906). pp. 



159-160. 



SCHOUTEDEN in Ann. Biol. lacustre, I, 3 (1906), pp. 335-336. 

 BROWN in Naturalist, 1910, p. 93 ; in Brit. Assoc. Handb. Sheffield, 



(1910), p. 500 ; in Scott. Natur. 1912, p. 112 ; op. cit. 1913, p. 146. 

 DADAY in Sitzb. Akad. Wien, CXIX, i (1910), p. 575. 

 COCKERELL in Univ. Colorado Stud. VIII, 4 (1911), p. 241. 



