APR 29 1924 
ON THE ERGOT OF EQUIDAE. 
By 
Schin. Yoschida. 
In 1913 I wrote the work entitled "Morphologische und Physiologische 
Bedeutung der Sogenannten Kastanie an den Gliedmassen der Equiden", for 
the Zoological Institute at Halle a. S. In this work, the outcome of a great 
deal of microscopic and macroscopic study, I believe I have given a difinite 
answer to the question "What is a Callosity?" but I did not then give 
any results of histological research on the Ergot, a small hornified mass 
found in the tuft of hair at the back of the fetlock. Since that time I have 
made further histological observations, the results of which I give below. 
In order to do this I wish first to refer to the results of former zoologists. 
Flower, in "The Horse", says, "The Ergot in the horse corresponds to 
the Afterclaw in the tapir, which is of the greatest use to the animal". 
In 1903, Lydekker, in "Proceedings of the General Meetings for Scien- 
tific Business of the Zoological Society of London", Vol. i wrote a great 
deal on the subject of Callosities without mentioning the Ergot. Against 
Ewart's theory, published in "The Royal Society of Edinburgh", that the 
Callosity is a rudimentary toe, he wrote as follows : "A more important 
objection to the foot-rest theory is to be drawn from the fact that the fore 
Callosities are above the Carpus and are, therefore, too high to serve as foot- 
rests to any j^lantigrades, and as it is impossible that any change of position 
should have taken place, they never could have served as foot-rests." 
The hind Callosities lie, on the contrary, below the hock and are there- 
fore on a part of the leg which, by plantigrades is considered the foot surface ; 
but while the fore Callosities are altogether homologous with the hind, it is 
[Jour, of the College of Agr., Tohoku Imp. Univ., Sapporo, Vol. VI, Pt. S, June, 1915] 
