Nofe on the Shells of Schizodesma spengleri Linn. 
147 
the lower shell into about half a dozen pieces, while the upper shell 
remained intact. These experiments were repeated, and in one the animal 
fell on the hinge of the shells, the unexpected result being that the two 
shells opened widely and remained so as if tlie animal had been paralysed 
by the shock. 
This, therefore, appears to be sujficient explanation of the condition of 
the shells so characteristic of those found above high-water mark. 
