182 THE MICROSCOPE. 
instruction and study with recreation. A few weeks spent in this 
way will result in abundant fruitage for the winter months. 
ACKNOWLEDGMENTS.—From E. D. Bondurant, Tuskalosa, Ala., 
mounts of normal human kidney and ovary; from Dr. John E. 
Hays, Sweet Springs, Mo., slide of Bacillus tuberculosis; from 
George B. Causey, Janesville, Wis., photomicrographs of scirus and 
fibroma mamme. 
ZOO Y .* 
Tue Anatomy or Saut-Warer Sponors.t—Taking the Halichon- 
dria panicea as a familiar illustration, Hardy describes the 
anatomy. The surface is smooth, rising into low elevations, which 
are surmounted by crater-like openings. If the specimen is quite 
fresh and healthy, the existence of strong currents streaming out of 
these openings, or “oscula,”’ may be demonstrated by placing a 
drop of carmine dissolved in sea water in the neighborhood of an 
osculum, when the up-streaming current will carry the color in, 
some of the particles being drawn to the surface of the sponge, 
others penetrating through microscopical apertures or pores, causing 
a distinct coloration. Under a lens the surface of the sponge is seen 
to consist of a thin membrane, ‘‘ dermal membrane,” supported by a 
reticulum of spicules, which, under a low power of the microscope, 
appears as a net-work of interlacing bundles of spicules embedded 
in a gelatinous substance, the sponge-flesh, and lie more or less 
parallel to the surface of the animal. The spicules of the rest of 
the sponge are also gathered into interlacing bundles, but lie in all 
planes. Each of these spicules, which may be straight or slightly 
curved, has the form of a delicate, elongated, double-pointed rod, 
which in section appears rounded, with its sides parallel throughout 
the greater part of their extent. The sponge-flesh will be seen to 
be pierced by the pores mentioned above. The oscula will be seen 
in sections to be the orifices of large tubes, into which smaller 
canals open, the lumen of the large tube being eventually lost in the 
smaller ones. The pores open into spaces beneath the dermal 
membrane. The current enters through the pores, passes through a 
number of delicate canals into larger, and finally into the largest, 
emerging as exhalent currents of the oscular. These currents are — 
maintained by the lashing movements of flagella which line the 
walls of the enlargements mentioned. 
* Under this heading will be included all Abstracts relating to the Embryology, 
Histology, etc., of Vertebrates and Invertebrates. 
+Science Gossip, January, 1889. 
