SOILS AND MOSSES OF SPITSBKEGBN. 467 
however, are not uncoininon. Finger-like pseudopodia may be formed 
at all parts of the bod}'', but they are commonest at the posterior end. 
Two flagella arise in a slight pit at the anterior end, of which one is 
directed forwards and is between 1 and Ih times the length of the 
animal, and the other, which is a little longer, is directed backwards or 
slightly to one side, but is quite free from the body except at its point 
of insertion, thus differing from the corresponding flagellum in Cercomonas. 
In small specimens the relative lengths of the flagella are often greater, 
up to three times the body-length. A vesicular nucleus is usually clearly 
visible in living specimens at or just in front of the middle of the organism, 
and a single contractile vacuole can occasionally be observed near the hinder 
end. The usual length is about 15 ^u,, though occasionally small specimens of 
6/A to 10 yu, occur. The movements are usually jerky, both the flagella being 
held more rigidly than in most flagellates, the anterior one vibrating 
vigorously. 
The amoeboid stage (text-fig. 4) is less commonly observed. One flagellum 
is retained which is directed sideways and continues to vibrate vigorously 
while the animal moves forward with a single broad pseudopodium, the 
posterior end being rounded. As in the swimming stage, the nucleus is more 
or less centrally placed and is easily visible, but the contractile vacuole now 
lies anteriorly between the ecto- and ento-plasms. 
This species resembles the genera Cercobodo Krassilstchik and Dimastig- 
amceba Blochmann rather closely in many respects. From the former, 
however, it is distinguished by the true amoeboid movements of the sessile 
form, while the fine radiating pseudopodia which Blochmann mentions as 
being sometimes formed by Dimastigammha have not been observed. 
It occurred in only one of the present soil samples, but has been found on 
several occasions in small numbers in soil from Harpenden and from the 
Azores, W. Indies, and other localities. 
Sp. e. (Text-figs. 5, 6.) 
In its general appearance and movements this organism is somewhat like 
Allantion tachyploon (see p. 461). The length is usually about 18 /i, though 
individuals as small as 10 ^li or as large as 24 /t occasionally occur. The 
width is about half the length. The sides are straight and the ends both 
rounded. In section it is circular or slightly flattened " dorso-ventrally." 
The shape is persistent and the body not flexible, but finger-like pseudo- 
podia may occur at either end. These are usually about 4 yu, to 6 /it long, but 
occasionally a much longer one is formed. A stout flagellurn, slightly 
longer than the body, arises at the extreme anterior end, and is directed 
backwards as in A llantion. In most individuals a very short second flagellum, 
about 2/ito3/i in length, can be detected. Near the base of the flagella 
are two prominent contractile vacuoles, but the nucleus is usually indis- 
distinguishabla in the living organisms, and, as already mentioned, no 
34* 
