PROaRESS OF MICROSCOPICAL SCIENCE. 
87 
as to destroy all the soft parts, the animal leaves behind more than 
half its bulk of quartzose sand. 
The species may be named Amoeba sahulosa, and is probably a 
member of the genus Pelomyxa, of Dr. Greef.* 
The animal was first found on the muddy bottom of a pond, on 
Dr. George Smith's place in Upper Darby, Delaware County, but has 
been found also in ponds in New Jersey. 
When the animal was first noticed with its multitude of sand par- 
ticles, it suggested the probability that it might pertain to a stage of 
life of Difflugia, and that by the fixation of the quartz particles in the 
exterior, the case of the latter would be formed. This is conjectural, 
and not confirmed by any observation. 
A minute amoeboid animal found on Sj)irogyra in a ditch at Cooper's 
Point, opposite Philadelphia, is of interesting character. The body 
is hemispherical, yellowish, and consists of a granular entosarc with a 
number of scattered and well-defined globules, besides a large con- 
tractile vesicle. From the body there extends a broad zone, which is 
colourless and so exceedingly delicate that it requires a power of 600 
diameters to see it favourably. By this zone the animal glides over 
the surface. As delicate as it is, it evidently possesses a regular 
structure, though it was not resolved under the best powers of the 
microscope. The structure probably consists of globular granules of 
uniform size alternating with one another, so that the disk at times 
appears crossed by delicate lines, and at others as if finely and regu- 
larly punctated. The body of the animal measures from -^-^ to gL. of 
a line in diameter, and the zone is from ^^3^ to of a line wide. 
The species may be named Amoeba zonalis. 
The interesting researches of Professor Eichard Greef, of Marburg, 
published in the second volume of Schultze's ' Archiv f. Mikrokopische 
Anatomic,' on Amoibse living in the earth (Ueber einige in der Erde 
lebende Amoeben, &c.), led me to look in similar positions for Ehi- 
zopods. 
In the earth, about the roots of mosses growing in the crevices of 
the bricks of our city pavements, in damp places, besides finding 
several species of Amoeba, together with abundance of the common 
wheel-animalcule, Botifer vulgaris, I had the good fortune to discover a 
species of Gromia. I say good fortune, for it is with the utmost pleasure 
I have watched this curious creature for hours together. The genus 
was discovered and well described by Dujardin, from two species, one 
of which, G. oviformis, was found in the seas of France ; the other, the 
G. fluviatilis, in the river Seine. 
Imagine an animal, like one of our autumnal spiders, stationed at 
the centre of its well-spread net ; imagine every thread of this net to 
be a living extension of the animal, elongating, branching, and be- 
coming confluent so as to form a most intricate net; and imagine 
every thread to exhibit actively moving currents of a viscid liquid 
both outward and inward, carrying along particles of food and dirt, 
and you have some idea of the general character of a Gromia. 
The Gromia of our pavements is a spherical cream-coloured body, 
* * Archiv f. Mik. Anat.,' x., 1873, 51. 
