14 
nature of their habitat renders it certain that a rapid drying-up of the earth 
or sand, especially in summer, must often occur, during which the active life 
of these Amoeba? is interrupted— that is to say, the creatures become torpid, 
just as the Arctiscoidae do, a fact which Dr. Greef has shown in an essay on 
these latter animals, (2nd vol. of Schultze's Archiv.) Their power of retaining 
life is indeed wonderful. The outer tough coriaceous but transparent layer 
draws together as the surrounding medium becomes drier, and thus protects the 
inner softer granular parenchyme from drying up. Ia this perfectly motion- 
less and apparently lifeless state, the creatures are met with in dry sand, 
from the particles of which they are scarcely to be distinguished. But by 
moistening the sand in which they may have dried up thus for months, they 
regain quickly an active existence. 
The following species are described by Dr. Greef : — 
Amoeba temiola. The adult animal measures 0 35 to 0-4 mm. in greatest 
diameter = - to ~ English inch. 
Amoeba brevipes = —j- to ~- inch in size. 
grant/era = inch. 
These two species are probably only young specimens in early stage of 
development. 
Ammba gracilis. Wormlike in form, about ~ inch long. 
— • Amphizonella. Dr. Greef considers this creature to be rather a 
new genus altogether, of which he describes the following species, viz. 
Amphizonella violacca. Measuring about -~ inch. 
digitata. inch. 
■ flava. inch— adult size. 
These species will be characterised after we have given Greef s description 
of his typical Amoeba Terricola. 
This creature, found in dry earth and sand, looks exactly like a small 
particle of grit or silex, having a dull glassy surface, and a number of short 
stiff knoblike protuberances on its external surface. The body is of irregular 
shape, and divided by clefts or fissures ; it contains in its interior a number 
of yellow or brown-colored granules, which are seen in pretty active motion, 
streaming hither and thither, as they are impelled by the movement of the 
contractile sarcode. The locomotion of this land Amoeba differs strikingly 
from that of the water species. Its external transparent ectosarc is of a 
much firmer and tougher consistence than that of the water Amoeba, and 
the contraction of this ectosarc is much more powerful. The knotty protu- 
berances do not spread with a smooth flowing motion like the projected 
