174 THE COURTSHIP OF ANIMALS 



sacs to bursting size, and these bags then look as if they 

 acted as floats. When there are several hundred of these 

 sociable creatures the din is continuous, and may be heard 

 more than a mile off." 



From what has been said of the Amphibia, and especially 

 of the Newts, it would seem that, among the land verte- 

 brates at any rate, the sexual instincts in this lowest 

 or simplest form are satisfied with the discharge of the 

 germinal products. Many, however, have advanced a 

 stage further and reveal the rudiments of that instinctive 

 care for offspring which develops to higher and higher 

 grades as we ascend in the animal kingdom, till at last, 

 in the human race, where the offspring is desired for its 

 own sake, we ascend to the highest plane of all. The 

 varied means of expression which these rudimentary 

 instincts take in the Amphibia have already been dis- 

 cussed in " The Infancy of Animals," which preceded 

 this present volume, and hence no more need be said on 

 this head in these pages. 



