74 BRITISH FRESHWATER RHIZOPODA. 



the latter usually containing large quantities of ex- 

 traneous matter and miscellaneous food particles, and 

 always numerous clear corpuscles (the giansikdrper of 

 German naturalists) regarded by the earlier observers 

 as zoospores, but more recently proved to be albuminoid, 

 and probably a source of nourishment to the symbiotic 

 bacteria with which the body of the organism is 

 charged.* Nuclei in some species very numerous and 

 minute ; in others of the ordinary type, and fewer ; 

 contractile vacuole absent, its place being apparently 

 taken by numerous small watery-looking vacuoles dis- 

 persed through the endoplasm. Locomotion effected 

 by broad lobular or wave-like expansions of the frontal 

 ectoplasm, or by pseudopodia originating on any part 

 of the surface, the posterior extremity during active 

 movement appearing rounded, and being furnished 

 with short sub-persistent hyaline pseudopodia, or with 

 a spherical lobe of granular structure (less dense than 

 the substance of the body), the surface of which is 

 covered with villous processes. 



1. Pelomyxa palustris GREEFF. 

 (Plate VII, figs. 1-3.) 



Pelomyxa palustris GREEFF in Arch. f. mikr. Anat. X (1874), 

 p. 51, tt. iii-v; F. E. SCHULZE in Arch. f. mikr. Anat. XJ 

 (1875), p. 342, t. xix, ff. 6-8; GABRIEL in Morph. Jahrb. I 

 (1876), p. 541; ALLMAN in Jonrn. Linn. Soc., Zool. XIII 

 (1877), p. 271, f. 5 ; ARCHER in Q. J. Micr. Sci. XVII, 

 n.s. (1877), p. 337, t. xxi, ff. 10-15f; ENGELMANN in 

 Arch. ges. Physiol. XIX (1879), p. 1 ;.Bih'SCHLi in Bronn's 

 Thier-Reichs, I, 1 (1880), t. ii, f. 1; Mikros. Schaume 

 (1892), p. 216; and (Engl. transl.) Micros. Foams (1894), 

 p. 116; KOROTNEFF in Arch. Zool. exper. V1I1 (1880), 

 p. 476, t. xxxvi, ff. 6-23 ; LAPHAM in Amer. Jonrn. Micr. V 

 (1880), pp. 165, 197; LANESSAN Traite Zool., Prot. (1882), 

 p. 44, ff. 32, 33; RAY LANKESTER in Encycl. Brit. ed. 9, 

 XIX (1885), p. 842, f. iv, 5, 6; BERTHOLD Stud. Protopl.- 

 mech. (1886), p. 109, t. ii, f. 6; BLOCHMANN Mikr. Thierw. 



* Mrs. L. J. Veley, in ' Journ. Linnean Soc.,' Zool., vol. xxix, pp. 375-386. 

 t As P. lacustris in Zool. Rec. for 1877, Prot. p. 4. 



