164 RAYMOND BINFORD 
Methods of study 
Koltzoff (06) by his careful analysis of the effects on the sperm 
of solutions differing-in osmotic pressure, has cleared up many of 
the mysteries of the decapod sperm. According to his researches, 
the spermatozoa maintain their normal form in solutions of salts 
having the same osmotic pressure as sea-water. He also found 
that 5 per cent KNOs;, 2.8 per cent NaCl, 4.25 per cent NaNO;, 
18.5 per cent MgSQ,, 7 per cent glycerine and 25.65 per cent 
sugar solutions are isotonic with sea-water. Solutions of these 
salts at a lower concentration cause a deformation of the sperma- 
tozoa. 
For my studies, solutions of KNO;, NaCl and NaNO; were 
used. The spermatozoa taken from the seminal receptacle and 
placed in solutions of these salts isotonic with sea-water would 
remain many days without perceptible change. When they were 
placed in weaker solutions of these salts transformations occurred. 
In studying these changes I proceeded as follows: Spermatozoa 
from the seminal receptacle were placed in the serum of the 
crab’s blood or in the isotonic solutions of KNO;, NaCl, or NaNO3. 
In these solutions they were transferred to the slide, covered and 
examined under the high power of the microscope. Then, by 
placing a weaker solution of one of the salts at the edge of the 
cover-glass and allowing it to diffuse underneath, a slow change 
in the form of the spermatozoon was obtained. This change 
was thus followed in detail. It is to these changes that we will 
now turn our attention. 
By referring to figure 61, we may again call to our minds the 
normal condition of the mature spermatozoon which consists of 
a chitinous capsule, set in a protoplasmic cup. The capsule con- 
tains a tubule with an inner and outer cavity and, running through 
the inner cavity of the tubule, is the central body, the proximal 
end of which rests on the wall of the capsule. 
