THE LOBOSA 



digitiform pseudopodia. In this species there may be either one or 

 many nuclei. It may reach a size of 200 p in diameter. A. guttula 

 (Fig. 12, 4) is another very common species of small size, 30 p, which 

 shows slow undulating movements of the ectoplasm but rarely 

 protrudes definite pseudopodia. In Amoeba Umax (Fig. 12, 2), which 

 is slug-like in form, the end that is posterior in progression shows 

 a fan -shaped arrangement of short ridges, due probably to the 



FIG. 12. 



Different species of freshwater Gymnamoebida. 1, Dactylosphaera radiosa, x 260. 2, 

 Amoeba Umax, x 200. 3, Amoeba verrucosa, x 200. 4, Amoeba guttula, Duj., regarded as a young 

 form of A. proteus by Leidy. 5, Amoeba proteus. 6, Amoeba (Ouramoeba) vorax, x 130. N, 

 nucleus ; c.v, contractile vacuole ; F.v, food vacuole ; F, hyphae of a fungus. In Amoeba vorax 

 some of the large diatoms (D, D) upon which it *feeds and the approximate positions of the 

 nucleus and contractile vacuole are shown. (1, 2, 3 from Cash ; 4, 5, 6 from Leidy.) 



wrinkling of the surface in the vortex of the retreating axial stream 

 <see p. 69). 



The marine Amoebae have not yet been carefully recorded. 

 Amoeba crystalligera is often found in marine aquaria, and a species 

 .allied to the freshwater A. guttula has been found at Woods Hole 

 in America. Amoeba fluida was found in sea- water aquaria in 

 Freiburg by Gruber, and this with two other species were also 

 found by him in the Gulf of Genoa. 



