1. The present paper is a study of the growth of a clam (Siliqua patula) under natural conditions and over a wide range of latitude.

  2. Various constants derived from the growth data are compared for the different localities. For this species, over the range considered, growth in the southern localities as compared with the northern is initially more rapid but less sustained, leads to a smaller total length and is associated with a shorter life span.

  3. Reasons are presented for considering the relative growth-rate as a particularly significant constant leading to more sound biological conclusions than the use of the absolute growth-rate.

  4. On the basis of the relative growth-rate, current mathematical expressions for the course of growth are discussed and a formula used which emphasises Minot’s conception of a growth-rate constantly declining with age.

This expression
in which L = length at time t, e = base of natural logarithms, and B, c and k are constants, is found to graduate the extensive data in clam growth with significant accuracy.
1

We wish to acknowledge our indebtedness to Harold Hotelling of Stanford University for assistance in applying to this problem a method developed by him (1927), and for other advice on mathematical questions in the present paper.

2
Copyright © 1931 The Company of Biologists Ltd.
1931
You do not currently have access to this content.