GROWTH AND AGE AT MATURITY OF THE PACIFIC 
RAZOR CLAM, SILIQUA PATULA (DIXON) 
By F. W. WEYMOUTH, H. C. McMILLIN, and H. B. HOLMES 
CONTENTS 
Page 
Introduction 201 
The razor clam 202 
Anatomy 204 
Digestive system 207 
Nervous system 207 
Locomotion 207 
Spawning 208 
Time of spawning 208 
Relation of water temperature 
to spawning 209 
Larval development and growth of 
young 213 
Length of larval life as com- 
pared with other mollusks 213 
Time of setting and growth of 
young 214 
Mortality of young 215 
Page 
The razor clam — Continued. 
Growth of the adult 216 
Ring method of age determina- 
tion 216 
Growth in different localities — 218 
Maturity 224 
Age at maturity 224 
Size at maturity 227 
Relation of age and length to 
maturity 229 
Quantitative measures 229 
Maturity in other forms 230 
Beaches 231 
Commercial catch ^ 231 
Summary 235 
Bibliography 235 
INTRODUCTION 
In the spring of 1923 the senior author was engaged by the Bureau of 
Fisheries to undertake the investigation of the razor-clam fishery of Alaska. The 
following summer, accompanied by Mr. Holmes, he spent 8 weeks in the field, 
visiting the Cordova beds and those near Chisik Island, Cook Inlet. In March, 
1924, Mr. McMillin, who had been working on a similar problem for the State of 
Washington, entered the service of the bureau, and during the following summer 
accompanied the senior author for 10 weeks in the field, examining the beds at 
Cordova and those in the vicinity of Kukak Bay; the Washington beds were 
visited on the return trip. 
The data collected was worked up at Stanford University by Mr. Holmes in 
the fall of 1923 and by Mr. McMillin during the fall and winter of 1924-25, under 
the supervision of the senior author. All general conclusions are the results of 
discussion and agreement of the three authors. 
201 
