748 The American Naturalist. [September, 
three,) the number of congenitally blind would increase, and, 
eventually, they would, in their turn, preponderate in num- 
ers. 
It is also possible that the longevity of cave animals, owing 
to the absence of ordinary enemies and of casualties, such as 
occur in the upper world, even though the supply of food were 
greatly restricted, would be much greater than in epigaean 
regions. If this be so, then there is a more favorable oppor- 
tunity for the development and fixation of the myopic condi- 
tion in subterranean situations. 
It thus appears that while the heredity of acquired charac- 
ters was, in the beginning, the general rule, as soon as the con- 
genitally blind preponderated, the heredity of congenital char- 
acters became the normal state of things, the inhabitants being 
all blind, and for generations breeding true to their specific 
and generic characters. 
On the other hand if the conditions should be changed, and 
the cave become opened to the light, then we should expect a 
gradual reversion to their eyed ancestors. This process would, 
of course, be due to causes exactly opposite to those producing 
the blind form, i. e., the presence of light, etc. In such a case, 
neither natural selection: nor panmixia would be the factors, 
although some one might give a high-sounding, “scientific” 
name to the supposed process. And this shows how inopera- 
tive can be natural selection or panmixia as true working 
causes of the transformation of species, compared with the 
operation of the fundamental factors of organic evolution 
postulated by the Neolamarckian. 
List or Essays AND ARTICLES RELATING TO BLIND OR CAVE 
ANIMALS PUBLISHED Since 18875 
A. The general subject, including anatomical, physiological, and 
theoretical considerations. 
Ciaccio, G. V. Osservazoni intorno alla membrana del 
-Descemet e al suo endotelio con una descrizione anatomica dell’ 
5 This list is supplementary to that te in my essay on the Cave Fauna 
of North America Memoirs of the National Academy of Sciences, 1889, and 
includes some titles omitted in that bian many of which are copied from 
Ritter’s work. 
