350 The Origin of a Small Race of Turkeys. [April 
(for example, in Oscarula lobularis, according to K. Heider). The 
difficulties presented by Trichoplax are heightened not only by 
our ignorance of the development, but by our lack of any facts 
from which to determine the physiological functions of the sev- 
eral layers of the body. Thanks to the kindness of Professors 
F. E. Schulze and Claus, I was enabled in 1883 to study Tricho- 
plax both at Graz and Vienna, and to fully confirm the histologi- 
cal discoveries of the former investigator. My experiments on 
the manner in which the animal fed gave purely negative results, 
for it would take no solid food at all, thereby lending counte- 
nance to the view that Trichoplax depends on fluid nourishment 
one. 
Bütschli thinks the Placula theory is of more value from a 
physiological point of view than the other theories criticised by 
him. “Finally, it seems to me very important,” says Bütschli 
(l. c., p. 416), “ that the changes undergone by the assumed forms 
are easily comprehended, that they take place gradually, not by 
jumps, and are actually advantageous.” “Especially in this 
latter respect,’ adds Biitschli, “is the new view about to be de- 
veloped superior to its predecessors.” When, however, it comes 
to explaining physiologically the origin of the placula, no satis- 
factory reasons are given why it should arise. “I regret that I 
am unable to adduce,” Biitschli confesses himself (p. 419), “any 
plausible advantages to be gained by the plate on its becoming 
two-layered.” 
. (To be concluded.) 
THE ORIGIN OF A SMALL RACE OF TURKEYS. 
BY JOHN DEAN CATON, LL.D. 
Me effect upon the progeny of animals of inbreeding, or 
where the parents are nearly related, is a subject well 
worthy the attention of naturalists, though I am not aware 
that it has been the subject of careful study, especially among 
the lower forms of animal life. 
With man it has undoubtedly received much attention, but 
even here it has been rather of a desultory character than that 
careful and systematic attention which its practical importance 
