SEXUAL SELECTION 301 



not even tHe wasp, wliich is closely allied to the bee, is pro- 

 vided witli a pollen- collecting apparatus, we have no grounds 

 for supposing that male bees primordially collected pollen aa 

 well as the females; although we have some reason to sus- 

 pect that male mammals primordially suckled their young 

 as well as the females. Lastly, in all cases of reversion, 

 characters are transmitted through t,wo, three, or many more 

 generations, and are then developed under certain unknown 

 favorable conditions. This important distinction between 

 transmission and development will be best kept in mind by 

 the aid of the hypothesis of pangenesis. According to this 

 hypothesis, every unit or cell of the body throws off gem- 

 mules or undeveloped atoms, which are transmitted to the 

 offspring of both sexes, and are multiplied by self- division. 

 They may 'remain undeveloped during the early years of 

 life or during successive generations ; and their development 

 into units or cells, like those from which they were derived, 

 depends on their affinity for, and union with, other units 

 or cells previously developed in the due order of growth. 



Inheritance at Corresponding Periods of Life. — This ten- 

 dency is well established. A new character appearing in 

 a young animal, whether it lasts throughout life or is only 

 transient, will, in general, reappear in the offspring at the 

 same age and last for the same time. If, on the other hand, 

 a new character appears at maturity, or even during old age, 

 it tends to reappear in the offspring at the same advanced 

 age. When deviations from this rule occur, the transmitted 

 characters much oftener appear before than after the corre- 

 sponding age. As I have dwelt on this subject sufficiently 

 in another work," I will here merely give two or three in- 

 stances, for the sake of recalling the subject to the reader's 

 mind. In several breeds of the Fowl, the down-covered 

 chickens, the young birds in their first true plumage, and 



=3 "The Variation of Animals and Plants under Domeatication," vol. ii., 

 1868, p. 75. In the last chapter but one, the provisional hypothesis of 

 pangenesis, above aUuded to, is fully explained. 



