30 



HALF-HOURS IN THE GREEN LANES. 



ten days or a fortnight, the young remaining in the 

 nest until the yolk-bag is absorbed. This is the 

 signal for the male to leave them to themselves, for 

 they are now supposed to be able to start in the 

 world for themselves, and no longer to require 

 paternal supervision. Not unfrequently, the con- 

 Fig. 18. 



Three-spinecl Stickleback and Nest. 



stant care on the part of the parents in guarding 

 the nest when the young are there, results in death. 

 Indeed, it is a common occurrence for the parents 

 to sicken and die through overmuch watching. 

 These facts in the history of, perhaps, the com- 

 monest of our piscine tribes, render it a most 

 interesting object for the aquarium. Among other 

 allied species to be met with are the Smooth-tailed 



