900 THE ANIMAL KINGDOM. 



able. Ampkizonella with a gelatinous envelope retains a more or less 

 globular shape ; its motions are very slow; its digitiform pseudopodia 

 perforate the envelope at any point. With a protoplasm of medium 

 density and ectosarc as a well-marked hyaline border, the pseudopodia 

 may have the form of small lobes with hyaline borders, or of conical and 

 pointed ectosarcal processes, occasionally of some length. Locomotion is 

 effected solely by their means or in combination with lobular protrusions. 

 In Amoeba lucida the extremities of the pseudopodia are apt to become 

 spirally twisted. Noticeable peculiarities are, the termination in the Tes- 

 tacean Petaloptis of the pseudopodia in plate-like ends, their transformation 

 in the naked Plakopus and Amoeba cellarum into protoplasmic membranes 

 uniting together so as to include funnel-shaped spaces, the villiform proto- 

 plasmic processes covering both body and pseudopodia in some specimens 

 of Dactylosphaerium vitreum, and the somewhat similar rigid spinules of 

 Deinamoeba (Leidy). The last-named is occasionally invested with a gela- 

 tinous coat, beset with minute vertical rods, possibly of Bacterial nature. 



Very many Nuda possess while in motion, especially flowing motion, 

 a patch of villous processes at the posterior extremity of the body. If the 

 protoplasm is very fluid, the villi are fine and cilia-like, but are seldom 

 seen ; if somewhat dense, they are pointed and filamentous ; if denser 

 still, stout and blunt. Their significance is unknown. The genus Our- 

 amoeba of Leidy is characterised by having in the same position motionless 

 trailing filaments, cylindrical, tubular, sometimes branched or jointed, ag- 

 gregated in bundles. It is possible that they are the mycelium of a fungus. 

 Indeed, many Amoebae contain rod-like bodies of varying length, especially 

 aggregated round the nuclei, and the only probable explanation of their 

 nature is that they are symbiotic fungi x . 



The protoplasm may contain colouring matters, sometimes derived 

 from the diatomin or chlorophyl of the food, sometimes intrinsic like the 

 green or yellow globules of Dactylosphaetium t the green, brown, or red 



1 Korotneff states that the appendages of his Longicauda, = Ouramoeba, amoebina, undergo 

 changes under unfavourable circumstances, the contents of the filaments becoming segmented into 

 small squarish highly refractile bodies (? spores) ; A. Z. Expt. viii. 1879-80, p. 472. In Leidy's 

 0. vorax the filaments are said to be cylindrical tubes, in 0. botiilicauda they consist of a series of 

 elliptical joints, 1-4, adapted end to end. Leidy says they resemble mycelial filaments ; see his 

 PI. ix. in the Fresh-water Rhizopoda, &c. Gruber thinks they are fungoid, and mentions that he 

 has seen the fungoid filaments of Amoeba binucleata protruded in bundles under the action of 

 chromic acid; Z. W. Z. xli. p. 211. 



Rod-like bodies, probably of fungoid nature, are very common in Amoebae and Pelomyxa ; see 

 especially Gruber, Z. W. Z. xli. p. 2 10. The ' Glanz-korper ' or ' glittering bodies ' of P. palustris, 

 are probably of parasitic origin (? Chytridian), and the source of the amoeboid and flagellate spores 

 seen by Greeff, Korotneff, and Weldon (cf. Ray Lankester, Encycl. Brit., ed. ix., xix. p. 842). Accord- 

 ing to Leidy they are present in P. villosa, but Gruber did not observe them in that species, nor 

 Korotneff in P. parvialveolata, Gruber found very similar bodies in Amoebae, particularly in 

 A. qninta ; see Z. W. Z. xli. pp. 191, 209. Biitschli says he has seen spore-like bodies with mem- 

 brane and nucleus, in Pelomyxa (pahistris?) ; see his Protozoa, Bronn's Thierreich, i, note, p. 159. 



