84 
to take in hand and re-examine this subject, since this can 
be done so easily. The water and earth which is wanted for 
the experiment is readily found everywhere and at any time 
within the ever-extending boundaries of this metropolis. If, 
then, the new experimentalists come to the same conclusion, 
I would leave them to decide whether Greef’s Ameba be 
or not entitled to its assumed name of ¢erricola. 
About the other two forms of A. granifera and gracilis I 
am quite disposed to agree with Dr. Greef, as far as the 
ameeboid nature of the creatures is concerned. Their flowing, 
for a practical eye, readily distinguishes them from the saz/- 
ing habit of the Coryeia. Forms, however, like these will 
easily be discovered, as I am convinced by experience, in the 
same London water, especially the A. gracilis, which is an 
extremely minute form, the opposite pole, I would say, of the 
comparatively gigantic A. villosa of Dr. Wallich, which, 
however, has the same nature. 
A very singular discovery, owed entirely to the ingenuity 
of our German doctor, is that quaint double form of Amphi- 
zonella violacea, digitata. As to his A. flava, I am rather in- 
clined to consider it as another form of Corycia, scarcely 
differing from C. Diyardini. 
Thus I would consider Greef’s Fig. 13 (Ameba brevipes 
‘in der Theilung begriffe’) as a mere incomplete stage of 
Amphizonella digitata. 
I should not wonder so much at his having found a dead 
and empty test of Arcella arenaria (?) as I really do at his 
having found it living, not only, but protruding such a mass 
of sarcode, as is rarely the case with the fresh-water Arcelle. 
JOSEPH GAGLIARDI. 
P.S.—For those who are not well acquainted with 
Dujardin’s genus Corycia, we beg to subjoin his diagnosis: 
** An ameeboid being covered by a very expansible, elastic, 
flexible membrane or sac, which becomes folded in different 
directions by the movements and contractions or expansions 
of the animalcule. The whole organism sometimes, after it 
has several times turned on itself, looking like a folded piece 
of linen...... The contents consist, besides sarcode, of granules, 
vacuoles and forming particles; the first named move in 
currents from one part to another. The expansions are not 
pushed forward, nor do they glide along the surface of 
reptation like those of Arcellina or of naked Amabe ; they 
proceed from various points of the general mass or body, and 
seem to serve rather to change the centre of gravity than to 
furnish a point @apput. 
