XAKED LOBOSE RH1ZOPODS. 



33'J 



no portions of the exterior of Deinanweba are constant, although they usually seem tc be so. Head 

 and tail appear to be mutually interchangeable ; and such also is the case with the processes I 

 have for convenience distinguished as pseudopods and papillae."* 



XIII. F. E. Schulze's Mtutuyanueba't and the DactylotpJtaeriwm^ described by Hertwig and 

 Lesser, are said by Leidy to have some resemblance to Deinamceba. But the former, about 1 millim, 

 long, is broad, and tapering at the ends, with many pseudopods and a general investment of minute 

 spiculate bodies, different from those of Deinanm-ba, and 

 a long flagellum projecting in front from an ovate cor- 

 puscle, enclosing a nuclear body. (See Fig. 4.) 



The latter has no flagellum, is irregularly round, 

 O06 millim. in diameter, with somewhat conical blunt 

 pseudopods in all directions; and one variety has minute 

 villi of protoplasm, also differing from those of Dein- 



XIV. Podostoma has relatively large pseudopods Fig. 4. MASTIGAXKEKA ASPEKSA, AS SEEN LUEEF- 

 for locomotion, and others for feeding. 1NG OVEK THE VIELD OF THE MICROSCOI-B. 



An intermediate form between the Rbizoppda and the Flagel- 



XV. Among other Amcebans we may note A. 'ate infusoria. Highly magnified. (Copied from Annum. 



* after Schalzc.) 



polypoda, found by Max S. Schultze in the lagoon- 

 water at Venice. This is near A. radiosa of fresh water. His A. por recta, from the Adriatic, 

 differs from a true Amoeba in its delicate and branching pseudopods. Wallich, however, has 

 pointed out that here, and sometimes with A. villcsa, the usual short thick pseudopods are replaced by 

 the finer filaments characteristic of the Filose Amoebans ; and that we must not draw too sharp a line 

 in classification when only one, and that not an essential, feature is used for the basis in grouping. 



XVI. The Amoeban animalcules which we have already mentioned are members of the group 

 known as the Naked lobose Rhizopods ; and these are necessarily of the highest importance to the 

 naturalist searching for explanations of the ways and means of all Rhizopoda; for, being 

 transparent, or nearly so, they allow of a direct scrutiny into their internal organs (if their 

 differentiated parts may be so termed), and such an insight to be got of their physiological functions 

 as comparisons with other known organs and functions will enable us to make. There are other 

 closely-allied Rhizopods with thick pseudopods, but they have delicate coats, tests, or shells, of 

 various composition and structure, and yet for the most part not interfering with a direct 

 acquaintance with the interior of the animal. They creep along with the aperture of the 

 shell downwards, and the pseudopods, spreading out from it, attach themselves to the surface on 

 which they crawl. 



XVII. Of these "Shelled Lobosa," the Diffluyia^ is one of the most common kinds, and 

 comprises many so-called species, which, however, together even with some allied genera, are probably 

 only varieties of one typical form. The shell is very variable in shape and substance ; globular, 

 or oval, with or without a neck, like a balloon, an urn, an amphora, a pitcher, a vase, a broad- 

 mouthed flask or bottle, with endless modifications ; opening downwards at what is usually the 

 narrow end ; the base sometimes pointed, instead of being round or flat, and the sides occasionally 

 armed with spikes ; the shell in many cases oblique, one-sided, or otherwise asymmetrical, and even 

 partially curved on itself, like a chemical retort, when, as Dr. Wallich has explained, the animal has 

 adhered to some object under the influence of a current of water pushing it over to one side. Its 

 composition is tough in tissue, like chitine ; but it has been originally soft enough (or has had an 

 occasional overcoat thrown back over it soft enough) to be encrusted with embedded sand, Diatoms, 

 spicules, &c., sometimes neatly fitted together, or even arranged with a parallelism when the com- 

 ponent Diatoms are large and long. 



In allied forms (QuadnUa, <fec.) the envelope has hardened in segments on some geometrical 

 plan, so that it is formed of little tablets, six-sided or square, edge to edge. Whether the tough 

 test-matter is secreted by the ectosarc, or the latter becomes superficially consolidated, is not known. 



* Leidy, Op. cit., p. 87. t Greek, mnatix, montif/os, a whip ; ama'ld. 



J Greek, (lactyl.os, a finger, or a date ; tsphaira, a sphere or ball. 



Greek, pous, a foot ; stonui; a mouth , Latin, diffluo, I flow in different directions. 



