22 



Cleared up many of the mysteries of the decapod sperm. Accord- 

 ing to his researches the sperms maintain their normal form 

 in solutions of salts having the same osmotic pressure as 

 sea-water. He also found that 5'^ KNO3. 2.8^ HaCl, 4.25^ UalTOg, 

 18.5^ MgS04, 1% glycerine and 25.66/S sugar solutions are 

 isotonic with sea-water. Solutions of these salts at a lower 

 concentration cause a deformation of the sperms. 



For my studies solutions of KHO3, UaCl and BiaH03 were 

 used. The sperms taken from the seminal receptacle and placed 

 in solutions of these salts isotonic with sea-water would re- 

 main many days without perceptahle change. When they were 

 placed in weaker solutions of these salts transformations oc- 

 curred. In studying these changes I proceeded as follows: 

 Sperms from the seminal receptacle were placed in the serum 

 of the crab's blood or in the isotonic solutions of KNO3, 

 HaCl, or HaHOg. 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 dif- 

 fuse underneath, a slow change in the form of the sperm was 

 obtained. This change was thus followed in detail. It is to 

 these changes that we will now turn our attention. 



By referring to Pig. 61 we may again call to our minds 

 the normal condition of the mature sperm which consists of a 

 chltinous capsule, set in a protoplasmic cup. The capsule 

 contains 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. 



