MagcuH 8, 1912] 
The actual frequency of offspring derived 
from each mating is given on the left of the 
table; the expected proportions in the more 
complex cases being given above the actual 
findings in parenthesis. The matings were 
made and the offspring examined in major 
part at the New Hampshire Agricultural Ex- 
periment Station and in minor part at the 
Station for Experimental Evolution. The 
latter station was able to contribute especially 
to the results of later generations. For 
horned females, Dorsets were used; for horned 
males Rambouillets, Dorsets and the Scottish 
4-horned race. As hornless races the Downs 
were chiefly employed. It is not our purpose 
now to give complete details, as the experi- 
ments are being continued and full data will 
be deferred until the publication of our final 
report. 
The results of the table accord very closely 
with expectation, so that we are justified in 
concluding that an explanation of the results 
like that we offer is the correct one. By our 
formula, then, the case of inheritance of 
horns in sheep is brought quite into line with 
that of other sex-limited characters, its pecul- 
‘jarities being due to an inhibitor of horn de- 
velopment that is carried in the sex-chromo- 
some. 
LITERATURE CITED 
Bateson, W., 1909, ‘‘Mendel’s Principles of He- 
redity,’’ Cambridge, Eng., University Press. 
Castle, W. E., 1911, ‘‘Heredity in Relation to Evo- 
lution and Animal Breeding,’’ New York, Ap- 
pleton. 
Guyer, M. F., 1910, ‘‘ Accessory Chromosomes in 
Man,’? Biol. Bull., XIX., 219-234, Pl. I. 
Wood, T. B., 1905, ‘‘ Note on the Inheritance of 
Horns and Face Color in Sheep,’’ Jour. Agric. 
Scet., I., 364, 365, Pl. IV. 
T. R. ARrKELL, 
C. B. Davenport 
DuruaM, N. H., 
CoLp Spring Harsor, N. Y., 
January 29, 1912 
THE “STOMACH STONES” OF REPTILES 
GastTroLitHs have been known to occur, 
mingled with the remains of extinct reptiles, 
SCIENCE 
317 
for many years and much attention has been 
called to them in the pages of ScieNcE and 
elsewhere, especially by Mudge, Seeley, Willis- 
ton, Eastman, Wieland and Brown. Interest- 
ing parallels have been cited among several 
living vertebrates. There has been some con- 
tention that the stones were taken for the pur- 
pose of a “gastric mill,” but they were in 
part at least accidental. There seems to be 
some evidence for the conclusion that the 
plesiosaurs, at least, selected stones for this 
purpose, though this may have been more 
accidental than we think. Recently there has 
been brought to my attention by Mr. Edward 
Taylor, of the University of Kansas, an in- 
teresting case of stone swallowing by a lizard, 
Phrynosema cornutwum Harlan. Only a 
single specimen is at hand for the data, but it 
is of sufficient interest in connection with 
identical habits among fossil reptiles to be re- 
corded. The horned “toad” in question is a 
very large adult female collected by the late 
Dr. F. H. Snow in the Magdalen Mountains. 
of New Mexico. In the stomach were twenty 
large, somewhat abraded stones of a rock 
which resembled lava. Some of the stones 
are very large, for the size of the animal, 
measuring nearly a third of an inch in diam- 
eter. There were also in the stomach about 
200 of the large red ants, of an undetermined 
species, which make the large mounds so 
common to the western traveler. The animal 
had undoubtedly picked up the stones with the 
ants from the top of the mound and the as- 
sociation is probably accidental. That they 
served the purpose of a “gastric mill” once 
inside the digestive canal can not be doubted, 
whether the animal willed or no. 
In this connection it may be of interest to 
the readers of these pages to call attention to 
some large Cretaceous sharks which have, 
within the past few months, been received at 
the University of Kansas Museum. In one 
specimen, consisting almost entirely of scat- 
tered vertebral cartilages, there are associated 
many hundreds of greatly abraded, very 
smooth and polished stones of white and 
black quartzite. That they belong with the 
shark can not be doubted on account of the 
