Geology and Natural History. 71 
swallowed with its food. The animal might be viewed as a bag 
of sand! It is a sluggish creature, and when at rest appears as 
an opaque white, spherical ball, ranging from } to 3 of a line in 
diameter. The animal moves slowly, first assuming an oval and 
then a clavate form. In the oval form red 2 of a line 
long by 2 of a line broad, and when it became clavate it was % of 
a line long by 4 of a line broad at the advanced thick end. An- 
other, in the clavate form, measured { of a line long by 4 of a line 
wide at the thick end. The creature rolls or extends in advance, 
while it contracts behind. Unless under pressure it puts forth no 
strong 
mineral acids so as to destroy all the soft parts, the animal leaves 
ehind more than half its bulk of quartzose sand, 
he species may be named Amapa sABULOSA, and is probably 
a member of the genus Pelomyaa, of Dr. Greef (Archiv f. Mik. 
Anat., x, 1873, 51). 
The animal was first found on the muddy bottom of a pond, on 
Dr. George Smith’s place in Upper Darby, Delaware County, but 
a found also in ponds in New Jerse 
en th 
particles, it suggested the probability that it might pertain to a 
e of life of Difflugia, and that by the fixation of the quartz 
topes in the exterior, the case of the latter would be formed. 
18 Is conjectural and not confirmed by any observation. _ 
minute ameeboid animal found on Spirogyra in a ditch at 
zone the animal glides over the surface. As delicate as it is, it 
evidently possesses a regular structure, though it was not resolved 
~ animal measures from siz tO py of a line in diameter, and the 
Zone is from s45 to x3, of a line wide. The species may be named 
Amapa ZONALIS. 
The interesting researches of Prof. Richard Greef, of Marb 
published in the second volume of Scholtze’s Archiv f. Mikr 
°plsche Anatomie, on Amb living in the earth (Ueber einige 
urg, 
kro- 
