ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
51 
Protozoa. 
Organization of Amoebae.* — Prof. B. Greef calls attention to the 
presence of motor fibrils in the exoplasm of Amceba terricola. He fixed 
active, strong and large examples of A. terricola by suddenly treating 
them with osmium, and examined them either directly after washing 
with water or after treatment for a short time with weak spirit. If the 
pseudopodia of a multinucleate terrestrial Amceba so prepared are exa- 
mined with high powers, they .and the whole body may be seen to be 
surrounded by a d stinct doubly-contoured tegumentary layer, which is 
sharply marked off from the underlying exoplasm. Highly refractive 
dots may be followed inwards, and may be seen to be arranged with a 
certain regularity. If the exoplasm be examined further in there may 
be seen here and there fine continuous filaments which traverse this zone 
in a radial direction ; with care it will be seen that the filaments are 
connected with the bright dots. Prof. Greef cannot doubt that w r e have 
here to do with muscular fibrils which traverse the contractile outer 
zone in a radial direction, and are inserted into the inner surface of the 
outer “skin.” In the ordinary uninucleate A. terricola the fibrils are 
much finer and difficult to follow. 
It is suggested that there are various phenomena in other Sarcodina 
which can be brought under this head— as the axial filaments of the 
Ileliozoa, which are perhaps the true motors of the pseudopodia, and 
the axial structures in the tentacles of Acinetae and others. 
Terricolous Amoebae. f — In another communication Prof. B. Greef 
dealt with the structure of the Amcebse found in mould. He is con- 
fident of the presence of a distinct cuticle ; if one adds a weak solution 
of methylen-blue it may be seen that, as soon as the colouring matter 
touches the surface, there is at first a fine blue band. Soon the colouring 
matter makes its way into the exopla6m, and then the stain shows up 
the blue folds and grooves which indicate the presence of a cuticle, moved 
by the underlying exoplasm. An excellent view of the cuticle may bo 
obtained by killing the Amoeba with osmium and immediately adding 
methylen-blue solution. On various occasions the author lias observed 
indications of eedysis or exuviation. Nutrition is effected at points 
where there is a temporary lesion. 
The author insists on the distinction between exoplasm and endo- 
plasm, urging that they differ in organization as well as in physiological 
significance. The exoplasm is, in the living Amceba, perfectly homo- 
geneous, hyaline and colourless ; there is nothing comparable to vacuoles. 
While the exoplasm is the motor zone of the Amoeba-body, the 
endoplasm has quite another character, both in organization and in 
function. It is soft and fluid, and follows the contractions of the outer 
zone, without taking any apparently active part in the movements of the 
body. The most important constituent of the endoplasm and that which 
gives it its peculiar character are the granules. Some of these are easy 
and others are very difficult to see ; the latter have, in fact, been hitherto 
overlooked ; these the author calls “glanzgranula.” In terrestrial Amceb® 
they are generally spherical in form, and they are surrounded by a fine, 
* Biol. Centmll)]., xi. (1891) pp. 599-COl, 633-40 
t Tom. cit., pp. 601-8. 
