334 W. C. M'INTOSH [may 1899 



further changes brought about by the high degreee of specialization in 

 the mammals, and by the fact that the procreative power is continuous 

 for a definite period after puberty. In the case of the annelid the 

 changes in the individual are evanescent or terminal, whereas in the 

 higher forms they are more or less permanent. 



The University, 



St. Andrews. 



