The Ohio JNJaturalist, 
and Journal of Science 
PUBLISHED BY 
The Biological Club of the Ohio State University. 
L!8HA 
NEW YC 
aoTANii 
Volume XV. 
APRIL, 1915. 
No. 6. 
TABLE OF CONTENTS 
Perry —The Inheritance of Size in Tomatoes. 473 
Walton —A Land Planarian with an Abnormal Number of Eyes. 498 
Bartlett— Key to the Seeds of the Wild and Cultivated Genera of Peas and Beans 
in Ohio.500 
THE INHERITANCE OF SIZE IN TOMATOES.* 
Fred E. Perry. 
INTRODUCTION AND STATEMENT OF PROBLEM. 
Only within the last decade has the attention of students of 
heredity been turned toward the solution of the problem of the 
inheritance of quantitative characters. From the very beginning 
of the science of genetics qualitative characters have been studied 
until, by means of a series of brilliant discoveries, our knowledge 
of their inheritance has increased in a wonderful manner. Very 
little progress has as yet been made, however, in the study of 
quantitave characters and the inheritance of them has been 
exceedingly difficult to analyze. 
Our present knowledge of heredity has been gained from a 
microscopical study of the germ-cells, from a statistical examina¬ 
tion of data bearing on heredity and from the experimental 
breeding of plants and animals. The last of the above named 
methods of studying heredity has been chosen for this work on the 
inheritance of size in the tomato. 
Size is a general term which means the measurement or extent 
of a thing as compared with something else or with a standard. 
It is applied to all kinds of dimensions great or small. The 
volume of a body is equal to the number of cubic centimeters 
which it contains; it is the amount or measure of tridimensional 
space. The mass of a body is defined as the quantity of matter 
*Contribution from the Botanical Laboratory of the Ohio State Uni¬ 
versity, No. 87. 
