116 
MR. H. N. MOSELEY ON THE ANATOMY AND 
I shall now proceed to describe in detail the anatomy of the Ceylon Land-Planarians, 
and also that of certain structures of some freshwater and marine species, after a short 
account of the methods employed in the investigation. 
Methods. 
The methods employed in the investigation of the anatomy of Planarians were the 
following : — 
In Ceylon the animals were placed, whilst still living, either in a large quantity of 
strong alcohol, this alcohol being changed after the lapse of twenty-four hours, or they 
were put into a weak solution of chromic acid, the solution being gradually strengthened 
as they became rigid, when, after remaining in the chromic-acid solution for about a week, 
they were transferred to strong alcohol. As soon as the specimens reached England they 
were placed in absolute alcohol. Portions of the bodies of the animals thus prepared 
were imbedded in the usual manner in a mixture of sweet oil and white wax. Sections 
were made in various directions with razors wetted in absolute alcohol * ; they were 
stained with a simple solution made by boiling carmine in water with a few drops of 
ammonia solution, and leaving the resulting fluid exposed to the air in order to obtain as 
neutral a solution as possible. The sections, after being stained and washed with water, 
were treated with absolute alcohol, rendered transparent with oil of cloves and mounted 
in dammar varnish. All the operations had, in the majority of cases, to be performed 
on the glass slide, the sections being too fragile to allow of transference. Some sections 
were also mounted at once in dammar varnish unstained, especially those prepared 
from specimens hardened in chromic acid. Some of the minuter details of structure 
were best to be observed in the chromic-acid preparations, and the nervous system espe- 
cially was only to be seen, with any clearness, in sections made from specimens thus 
prepared ; but it is almost impossible to prepare sections of large area from such speci- 
mens, owing to the brittleness of their tissue. Such sections were therefore made from 
animals hardened in alcohol, and the relations of the various organs to one another thus 
determined. The sections of Dendrocoelum lacteum figured were prepared from speci- 
mens which had remained about a year in strong glycerine, and which were transferred 
thence to absolute alcohol before cutting. Specimens thus prepared afford far better 
preparations than specimens placed in alcohol directly. 
Lastly, dissections with scalpels and scissors of spirit specimens of Bipalium Dima 
were made under alcohol in the ordinary manner. 
The sections of the Sea-Planarian, Leptoplana tremellaris , employed were made from 
a specimen which had been preserved in ordinary spirit for a number of years, and not 
with a special view to histological examination. The sections were stained and treated 
in the same manner as those of the Land-Planarians. 
* Though it is expensive to use absolute alcohol for this purpose it is much better to do so. Absolute 
alcohol thoroughly wets a razor, forms an even film all over its surface, and allows a large section to he made 
with much greater ease than is the case if ordinary alcohol be employed. 
