LIMITATION OF FAMILIES 131 



large, sometimes enormous, have stout shells and enough food-yolk 

 for the nutrition of the embryo until it is fully formed. The numbers 

 are much reduced and the eggs are generally hidden in some 

 secluded place, in nests at the roots of plants, covered over with soil, 

 or wrapped in leaves on forest trees. In some of the snails of the 

 Pacific Islands only five or six eggs are laid, and these are preserved 

 in a special chamber near the mouth of the shell of the mother, 

 where they remain some time after they have hatched out as young 

 snails. 



In the various invertebrate animals the limitation of families 

 and the provision for the young are chiefly economic in character. 

 The supply of food and the protection afforded the young during 

 their most tender stages have brought about a greater security 

 that the species will be maintained. Incidentally, however, they 

 have been associated with considerable changes in the mode of 

 growth of the young. As these have no longer to secure their own 

 living, it is possible for the mode of development to be more direct 

 and for various ancestral stages to be cut out. It has led, more- 

 over, to very important modifications of instincts. We think of 

 the care bestowed by parents, and especially by a mother on the 

 young, as springing from affection, but it happens often amongst 

 invertebrates that such care is devoted to offspring that the parents 

 will never see and exhibited by animals to which it is difficult to 

 attribute any emotions. The emotional quality of affection really 

 comes later than the duties and cares and devotion of maternity. 

 It is a consequence and not a cause of parental care. The modifica- 

 tion of instinct that it reveals is very striking. The first business 

 of any animal is to look after itself, to provide for its wants, to 

 satisfy its own appetites, and especially in the case of carnivorous 

 creatures to regard every living and moving thing as prey to be 

 seized and devoured. The mere toleration of the young by the 

 mother is a new beginning in life, and is the foundation of many of 

 the highest qualities displayed by the highest animals and by man 

 himself. 



The relations of the young to the mother are less surprising. 

 They are a continuation of the organic relation by which the young 

 are born of the body of their mother, and they exist and become, so 

 to speak, a habit before the individuality, the physical powers and 

 the senses and aptitudes of the young are really awakened. And 

 so in the same way the relations of the young of the same family 

 to each other precede consciousness and real individuality. The 



