1886. | MR. J. B. SUTTON ON ATAVISM. 555 
prostate an unimpeachable witness of an ancestry with the feathered 
tribe, low down among the oviparous reptiles. 
Let me now proceed to show how very little information we possess 
concerning latent germs which may be present in the embryo. For 
example, the discovery of the germ of an os centrale in the carpus of 
man was certainly startling. Yet its existence might have been 
anticipated from what we know of the variations in the number of 
the carpal ossicles in the adult. Atavism drew the attention of 
anatomists to a secondary astragalus in the human tarsus, and Barde- 
leben succeeded in detecting the germ. (This has been questioned by 
Baur, but his objections are inconclusive.) We must now consider 
some cases of a different character. 
Atavism in relation to Secondary Sexual characters. 
As Darwin points out}, two distinct elements are included under 
the term “inheritance ’’—the transmission and the development of 
characters. The distinction is a most important one, especially in 
its bearing on the question of Atavism, that the two conditions will be 
illustrated by concrete examples. 
In most species of the Deer tribe it is the rule for the male alone 
to possess antlers, yet it is a well attested circumstance that under 
certain diseased conditions of the sexual organs, especially atrophy or 
degeneration of the ovaries, rudimentary horns which are never shed 
appear in the female. 
This shows us that although the female is in possession of the 
secondary sexual organs in virtue of transmission, yet they remain 
latent as a rule, and only become developed under extraordinary 
circumstances. The same holds good for those cases of hens who 
for years lay eggs, yet eventually cease to do so, put on one side the 
plumage proper to their sex, and adopt more or less completely the 
plumage of the cock. 
These examples open up the subject of secondary sexual charac- 
ters. The question of primitive hermaphroditism has been already 
discussed in a preceding paper, and an attempt was made to show 
that, for a brief period at least, the embryo presents sexual parts 
common to the male and female, so that for a time it is absolutely 
impossible to determine the sex. What is true of the embryo applies 
equally to animals normally hermaphrodite: no distinctive charac- 
ters are displayed externally. Also in cases of hermaphroditism 
occurring in animals normally bisexual, the secondary sexual charac- 
ters are intermediate to those of the functional male and female. It 
is therefore fairly evident that the female, though she differs from the 
male in the non-development of secondary sexual characters, yet 
possesses them in a latent condition; or, to put the matter briefly, 
they are transmitted, but not developed. 
‘This raises two questions, each of equal importance :—(1) How are 
these characters transmitted? (2) What hinders their development? 
It seems to me that the second of these questions is the one with 
which we are chiefly concerned here, and that the non- development of 
1 «Descent of Man,’ 2nd ed. p. 227. 
