CONTENTS. 



PAGE 



The Hydroida of the Pacific Coast of North America, by 



Harry Beal Torrey. Plates 1-11 1-104 



Introduction 3 



Distribution of Species 5 



Table of Distribution 8 



Condensed Table of Numerical Distribution of Species 16 



Table of Distribution by Species 17 



Key to West Coast Hydroida IS 



Systematic Discussion 26 



Bibliography 81 



A case of Physiological Polarization of the Ascidian 



Heart, by Frank W. Bancroft and ('. O. Esterly 105-114 



Introduction 105 



Experiments 107 



Deviations from Normal Behavior Ill 



Bibliography 114 



Embryology and Embryonic Fission in the Genus Crisia, 



by Alice Robertson. Plates 12-15 115-156 



Introduction 115 



Reproductive Processes 117 



Development of the Primary Embryo 133 



Summary 145 



Bibliography 147 



Correlated Protective Devices in some California Sala- 

 manders, by Marian E. Hubbard. Plate 16 157-170 



Bibliography 167 



Studies on the Ecology, Morphology, and the Speciology 

 of the Young of Some Enteropneusta of Western North 

 America, by William E. Ritter and B. M. Davis. 

 Plates 17-19 171-210 



(1) Tormina ritteri Spengel 171 



Occurrence 172 



Specific Characters and some Morphological Points of 



special Interest 1 74 



Ecology 186 



(2) Tornaria huobardi, n. sp 198 



(3) Absence of the tornaria stage in the Development of 



Dolochoglossus pusillus Ritter ( M S) 200 



Bibliography 203 



