150 NEST OF THE TEN-SPINED STICKLEBACK. 



by the 18th of June, and the second brood hatched 

 out successfully. I kept many of them till they 

 reached adult fishhood, and have some of them still, 

 including the original paterfamilias. I am not 

 aware whether among the three-spined species either 

 Gasterosteus aculeatus or leiurus form two or more 

 nests, or add to the size of the first as occasion may 

 require. The fact of the ten-spined kind carrying 

 on their operations in this way was only made 

 known to me by personal observation, as I was 

 previously under the belief that all our fresh- water 

 species performed their nidification in the same 

 manner. 



