68 BRITISH FRESHWATER RHIZOPODA. 



Dactylosphasrium vitreum HERTWTG & LESSEE in Arch. f. 

 mikr. Anat. X (1874), Suppl. p. 54, t. ii, f. IA (non IB) ; 

 ALLMAX in Journ. Linn. Soc., Zool. XIII (1877), p. 266, 

 f . 1 ; AECHEK in Q. J. Micr. Sci. XVII, n. s. (1877), p. 344, 

 t. xxi, f. 17; PAKONA in Boll. Sclent. II, an. 6 (1884), 

 p. 56; BLOCHMANN Mikr. Tliierw. Siisswass. (1886), p. 11, 

 t. i, f. 10, and ed. 2 (1895), p. 14, t, i, f . 7 ; G-. S. WEST in 

 Journ. Linn. Soc., Zool. XXVIII (1901), p. 310. 



Dactylosphseria polypodia BUTSCHLI in Bronn's Thier- 

 Eeichs, I, 1 (1880), t. i, f. 11. 



Dactylosphserium polypodium LANESSAN Traite Zool., Prot. 

 (1882), p. 48, f. 35. 



Dactylosphsera polypodia RAY LANKESTER in Encycl. Brit, 

 ed. 9, XIX (1885), p. 842, f. iv, 1-3 ; LONGI in Atti Soc. 

 Ligust. (1894), p. 16; DELAGE & HEROCARD Zool. concr. I 

 (1896), p. 99, f. 107. 



Amoeba vitrea PENARD Faune Rliiz. Leman (1902), p. 84, ff. 



According to the description given by Hertwig and 

 Lesser this species has a spherical or sub-spherical 

 body, from which radiate blunt or conical pseuclopodia, 

 in length usually about half the diameter of the body, 

 and, like the border, consisting of a " perfectly homo- 

 geneous, quite clear, glassy-looking plasma." Immersed 

 in the protoplasm are a great number of greenish, 

 strongly-refractive granules, varying in size. Two 

 forms of the organism are described, one being green, 

 the other a bright clear yellow. The coloured elements 

 are crowded, filling the body-mass all but the narrow 

 hyaline border, and preventing any view of the 

 nucleus. In most, if not all, of the examples of the 

 green form met with by Hertwig and Lesser, the entire 

 superficies, including the pseudopodia, was covered by 

 " peculiar protoplasmic hair-like prolongations, in 

 which, however, no movement was perceptible." 

 Amongst other points of distinction Hertwig and Lesser 

 say that the green examples lay motionless and at rest, 

 appearing as more or less regular balls, and only these, 

 with their numerous projected pseudopodia, showed a 

 slow forward or backward movement. With the 

 yellow-coloured individuals the case was different. 

 These not only moved with comparative rapidity, aided 



