260 PROGRESS OF MICROSCOPIOAL SCIENCE. 
the mouth ‘02 broad and ‘008. Others varied from ‘06 long and ‘08 
broad, to 092 long by :064 broad. 
In observing the Pocono variety of Hyalosphenia ligata, and the 
beautiful and well-marked species Hyalosphenia papilio, he detected 
an important point of structure which previously had escaped his 
notice. In the active condition of these, and other Difflugians, they 
are seen with one or more pseudopods extended from the mouth of 
the test, to the margin of which the sarcode is attached, as well as 
by diverging threads to various points of the interior of the test. 
The interval between the body of the sarcode and the interior of the 
test is occupied with water. The extent of the interval increases with 
the increase in number and extent of protrusion of the pseudopods, 
and also varies according to the degree of emptiness or repletion with 
food of the sarcode body. When the pseudopods are withdrawn into 
the mouth of the test, the mass of the sarcode expands in a corre- 
sponding ratio, and the threads of attachment to the inside of the 
test contract in length. The intervening water appears to be dis- 
placed through small apertures of the lateral borders and fundus of 
the test, which exist in numbers usually from two to half a dozen 
or more. 
While speaking of Rhizopods, he would ask the attention of the 
Academy to some remarks on recent observations on the habits of 
several species of Amceba. 
One of the species of Amceba which he had most commonly seen, 
he took to be the Ameba verrucosa of Ehrenberg, with which the 
A. natans of Perty, and the A. terricola of Greef, appeared to him to 
be synonymous. ‘This species he had found in many places: in the 
crevices of the brick pavement in the yard attached to his residence, 
in brick ponds, in the ooze of the rocky shores of the Schuylkill 
River, in sphagnum swamps, in marsh mud, &e. It is remarkable 
for its sluggish character ; and in appearance reminds one of a little 
pile of epithelial scales, or fragment of dandruff from the head. 
Appearing quadrately oval or rounded, transparent, and more or less 
wrinkled, or marked with delicate wavy lines; the pseudopods rise 
in short obtuse mammillary eminences or wave-like ridges, the sum- 
mits of which are composed of transparent ectosare, while the central 
portion of the body is occupied by a thin, pale, diffused, and finely 
granular entosare. This contains one or more vesicles, usually one, 
which very slowly enlarges, and then less slowly collapses. In 
addition, as part of the structure, an oval granular nucleus is some- 
times visible. The food contents generally appear not to be abundant, 
and often the creature appears to be empty of food altogether. The 
character of its food is the same as with other species of Amceba. 
It not unfrequently feeds on Difflugians. In a specimen from 
sphagnum water, from Vineland, N.J., last August, he observed an 
individual, about the 1, of a millimeter, containing a Difflugia and a 
Trinema together. As observed by him, the species ranges from 51; to 
1 of a millimeter in diameter. 
On the morning of August 27, from some mud adhering to the roots 
of Sparganium, obtained the day previously in a nearly dried-up 
