Vol. XL. April, 1921. No. 4. 



BIOLOGICAL BULLETIN 



AUTHORS ABSTRACT OF THIS PAPER ISSUED BY 

 THE BIBLIOGRAPHIC SERVICE, MARCH 14, 1921. 



THE ECOLOGY AND LIFE-HISTORY OF AMPHIGO- 

 NOPTERUS AURORA AND OF OTHER VIVIPAR- 

 OUS PERCHES OF CALIFORNIA. 



CARL L. HUBBS, 

 MUSEUM OF ZOOLOGY, UNIVERSITY OF MICHIGAN. 



TABLE OF CONTENTS. 



PAGE. 



Introduction 1 8 i 



Ecology 183 



Breeding season 185 



Sex-ratio in adults, young and embryos 186 



Early differentiation of the sexes, and natal maturity of the males 187 



Copulation, and the storage of spermatozoa 189 



Embryonic development and natal metamorphosis 191 



Period of breeding of females of different size and age 194 



Number of young born by females of different size and age 195 



The seasonal marks ( annuli) on the scales 197 



The metamorphic annulus 200 



Comparative size of the sexes at different ages 201 



Rate of growth 203 



Bibliography 208 



INTRODUCTION. 



As the life-history of these fishes is intimately correlated with 

 their viviparity, it may be of interest and pertinence to consider 

 first some of the main features of viviparity in fishes. Most 

 fishes are characterized by the prolific production of ova that are 

 fertilized in an almost fortuitous manner. Within the group, 

 however, some form of protection of the eggs has become re- 

 peatedly evolved, in correlation with a decrease in the number 

 of ova and with a less random fertilization. This protection is 

 variously accomplished by one or both parents, by the burying 

 of the eggs in relatively safe situations; the construction of 

 nests of gravel, plants or bubbles ; the driving of predatory 



181 



