MARCH 7, 1884.] 
which are all marine) had not heretofore been un- 
questionably established, Mr. Edward Potts believed 
that it would be of interest to record that he had in 
his possession specimens from the Schuylkill River 
above the dam, and therefore from absolutely fresh 
water. The currents produced by the cilia on the 
tentacles were claimed to be excurrent, and not in- 
current, as might have been expected, the feeding 
processes in some cases being performed by the ten- 
tacles themselves. 
Jan. 29. —Prof. J. Leidy directed attention to a 
collection of fossil bones which had been submitted 
to his examination by the Smithsonian institution. 
They were obtained at the mine of the American 
salt company, near New Iberia, La. They chiefly 
consist of remains of Mastodon americanus, of Equus 
major, of an Equus not distinguishable from the 
domestic horse, and of Mylodon Harlani. Of the 
Mastodon, the collection contained well-preserved 
molar teeth, and characteristic fragments of bones. 
Of the Equus major, there are vertebrae, fragments 
of long bones, and a number of teeth. Of Mylodon, 
there are several molar teeth, vertebrae, and other 
bones, mostly fragments. Among these are two ma- 
ture and well-preserved tibiae, the best specimens yet 
discovered of the species. They are identical in form 
and size with those of M. robustus, indicating M. Harla- 
ni to have been a species of the same size as the former. 
Prof. J. Leidy stated that he had recently received 
for examination, from Mr. B. W. Thomas of Chicago, 
several glass slides with mounted specimens of sand. 
These were obtained by washing clay from the bowl- 
der drift of Meeker county, Minn. In the specimens 
Professor Leidy recognized some well-preserved and 
characteristic foraminifera, of which two forms ap- 
peared identical with Sextularia globulosa and Ro- 
talia globulosa, now living in the Atlantic Ocean. 
The fossils Mr. Thomas supposes to be derived from 
a soft yellow rock, cretaceous shale and lignite form- 
ing part of the drift. He also reports the finding of 
fragments of marine diatoms in the clay. Professor 
Heilprin suggested that the foraminifera referred to 
had probably been washed from underlying Silurian 
rocks. 
Feb. 5. — A communication was read from Miss 
S. G. Foulke, describing a new species of rotifer 
under the name Apsilus bipera. The specimens were 
found in Fairmount Park; and, in common with 
all members of the genus, they possess, instead of 
rotatory organs, a membranous cup or net, which is 
used for the capture of food. The specific distinction 
of the form now described consists chiefly in the 
structure of the net, the presence of a true stomach 
in addition to the usual crop, and the presence of 
cilia inside the net. It was proposed to unite the 
forms Apsilus lentiformis Meczinchoff, Dictyophora 
vorax Leidy, Cupelopagus lucinedax Forbes, and the 
Species now described, under one genus, Apsilus, in 
consequence of their strong points of resemblance. 
These are, briefly, the presence of two eye-spots, of 
a membranous crop instead of rotatory organs, of a 
mastax exactly alike in all, and the absence of a tail 
or foot-stalk. 
SCIENCE. 
295 
Prof. H. Carvill Lewis announced the discovery of 
fossils in the triassic red shale from the neighborhood 
of Phoenixville, and gave a preliminary notice of 
them. They occurred in soft red rock at the south- 
ern entrance to the new tunnel, in strata dipping 10° 
* N. 80° W., which would place the bed considerably 
below the strata of the old tunnel, perhaps a thou- 
sand feet, unless faults intervened. The specimens 
consist of some five distinct species of lamellibranch 
shells, a ganoid fish, some plants, and a doubtful 
fragment of a saurian bone. Among the shells are 
two species of Unio, somewhat resembling U. cal- 
ceolus and U. lanceolatus of Lea. These are, of 
course, of fresh-water origin, and are found in single 
and double valves, and open. Three species of 
marine shells also occur in the collection ; and the 
apparent commingling of fresh-water and marine 
species was referred to as an interesting fact. The 
shells, which in most instances lay parallel with the 
bedding, were frequently distorted: by the movement 
of the shale. The Unios were regarded as probably 
the most ancient yet discovered, some specimens 
found in New Mexico being of later age. The coal- 
plants represented are fresh-water species, but refer- 
ence was made to a triassic marine fucoid described 
by the speaker some years ago. The fish belongs to 
the lepidoganoids, and resembles the Catopteris gra- 
cilis of Redfield. 
Engineers’ club, Philadelphia. 
Jan. 19.— Mr. Wilfred Lewis read a paper upon 
the resilience of steel, reviewing some of the means 
employed for the storage of energy, and showing the 
place occupied by steel among them. Among the 
means now employed, compressed air, hot water, and 
the storage battery were cited from an English writer 
as being about equal in value, and as giving out about 
6,500 foot-pounds of work per pound of material 
used. Steel springs, according to the same writer, 
were said to yield about 18 foot-pounds per pound. 
In this connection, the project of using steel springs 
as a motor for street-cars was referred to as the most 
hopeless of all possible means of locomotion. To 
test the accuracy of this statement in regard to steel, 
several experiments were made by the writer upon 
tempered specimens, both for tension and flexure. 
Contrary to expectation, the highest results were 
shown by the flexure of a small spiral clock-spring 
weighing 2,040 grains, which gave out, when wound 
up, about 45 foot-pounds of energy; or, in other 
words, 154 foot-pounds per pound. The transverse 
strength of this steel, within the elastic limit, was 
found to be about 300,000 pounds per square inch, and 
its modulus of elasticity about 30,000,000. Such ex- 
traordinary strength, with such a low modulus, was so 
far beyond conjecture, that it seemed to give a new 
hope for the success of the project referred to; but, 
after making the necessary allowances for weight of 
car and efficiency of driving mechanism, it was found 
that not more than about 20 foot-pounds per pound 
of car would be available for locomotion. It was 
therefore improbable that such a car could ascend a 
hill over twenty feet high. It was also a matter of 
