WhAI? t>LANl!s DO FOR THEIR YOUNG. 173 



not regarded as nuts in the strict botanical 

 sense), are the walnut, the hazel-nut, the coco- 

 nut, the chestnut, the acorn, the lime-nut, the 

 almond, and the hickory-nut. In the Brazil nut 

 the seeds (which are what we commonly call the 

 nuts) are enclosed in a solid shell like that of a 

 coco-nut, and are themselves also hard and nut- 

 like. In the chestnut the fruit is a prickly 

 capsule, inside which lie the seeds, which we 

 know as chestnuts. 



But why have some plants so many seeds and 

 some so few? Well, the simpler and earHer 

 types produce a very large number of ill-pro- 

 vided seeds, which they turn loose upon the 

 world to shift for themselves almost from the 

 outset. Many of them perish, but a few survive. 

 On the other hand, the more advanced plants, 

 as a rule, produce only a small number of seeds, 

 but each of these is well provided with starches 

 and oils for the growth of the young plant ; and 

 as most such survive, any tendency in the direc- 

 tion of laying by food-stuffs would of course be 

 favoured by natural selection. Just so among 

 animals, a codfish produces nearly a million 

 eggs, of which only two or three on an average 

 survive to maturity ; while a bird produces half 

 a dozen large and well-stored eggs, and a cow or 

 a horse rarely brings forth more than one calf or 

 foal at a birth. Decrease in the number of seeds 

 is a fair rough test of relative progress. 



In nuts, you can see at once, the seeds are 

 very richly stored, and the young plant starts 

 in life, able to draw for a time on these ready- 



