LECTURE VIII. 215 



latter. In most cases^ it is true, this family life in animals 

 extends only to one generation ; for when the young are able 

 to support themselves, they separate from the parents, and the 

 family connection is severed. Every year, or even a shorter 

 period, brings a new family, which again separates, to become 

 perhaps the heads of another family. It, however, occasionally 

 happens, as is the case with bears, that the eldest of the 

 young remains at home, being appointed nurse to the younger 

 generation, and is severely chastised by the mother if it 

 neglects any of its duties. Wherever the families remain 

 together, the society enlarges and a division of labour obtains, 

 so that the existence of the individual frequently depends on 

 family life. The herds of deer, antelopes, and buffaloes are 

 probably only the members of one family grown up together 

 and led by the oldest member of the herd. In such societies 

 the family bonds are slender enough ; but it is different in 

 such social animals as bees, ants, etc., in which the individuals 

 possess different forms and organisations, according to the 

 part they play in their domestic economy. 



The development of the young presents a series of con- 

 ditions greatly differing from those of advanced age, and a 

 very close examination is requisite for becoming convinced 

 that an animal in the larval state is transformed into a subse- 

 quent mature form. These deviations are so great, that up 

 to Cuvier's time certain animals were classified when young 

 as moUusca, and in the adult state among the articulata. 

 There are also the sexual differences. We have seen that in 

 man the physical differences between male and female are in 

 every respect greater than the differences existing between 

 individuals of the same sex in different races ; and we also 

 know that in many animals the sexual differences are so great, 

 that the closest examination is requisite to establish their rela- 

 tions to each other. 



In the lower animals we observe a series of development 

 stages, which only terminate after several generations, so that 

 not the child (so to speak) but the grandchild resembles the 

 parents ; and there exist, probably, more complicated family 

 connections, by which individuals seem to return to the origi- 

 nal form by a roundabout way. 



