LATENT TRANSMISSION. 207 
dividuals of which live isolated and possess an eye of the form 
of a horse-shoe, produce in a non-sexual manner (by the 
formation of buds) a completely different and smaller gene- 
ration. The individuals of this second smaller generation 
live united in chains and possess a cone-shaped eye. 
Every individual of such a chain produces, in a sexual man- 
ner (hermaphrodite) again, a non-sexual solitary form of the 
first and larger generation. Among the Salpz, therefore, it 
is always the first, third, and fifth generation, and in like 
manner the second, fourth, and sixth generations, that are 
entirely like one another. However, it is not always only 
one, but in other cases a number of generations, which are 
thus leapt over; so that the first generation resembles the 
fourth and seventh, the second resembles the fifth and 
eighth, the third resembles the sixth and ninth, and so on, 
Three different generations alternate with one another ; for 
example, among the neat little sea-buoys (Doliolum), small 
tunicates closely related to the Salpz. In this case it is 
= — D —G, further, B—E—H, and C—F—LI. Among 
the plant-lice (Aphides), each sexual generation is followed 
by a succession of from eight to ten or twelve non-sexual 
generations, which are like one another, but differ from 
the sexual generations. Then, again, a sexual generation 
reappears like the one long before vanished. 
If we further follow this remarkable law of latent or in- 
terrupted inheritance, and take into consideration all the 
phenomena appertaining to it, we may comprise under it 
also the well-known phenomena of reversion. By the term 
“reversion” or “atavism” we understand the remarkable 
fact known to all breeders of animals, that occasionally 
single and individual animals assume a form which has not 
