ZOOGEOGRAPHY AND ECOLOGY OF SOME MACRO- 

 INVERTEBRATES, PARTICULARLY MOLLUSKS, IN THE 

 GULF OF CALIFORNIA AND THE CONTINENTAL SLOPE 



OFF MEXICO! 



With Plates I-XV 

 By Robert H. Parker^ 



Woods Hole, Massachusetts 



Table of Contents 



Page 



Abstract 2 



Introduction 4 



Acknowledgments 11 



History of Biological Exploration in the Gulf of California 13 



Methods of Collecting and Analyzing the Data 16 



Description of the Region Sampled 26 



Geology and Topography 26 



Sediments of the Gulf of California 29 



Bottom Dissolved Oxygen Concentrations 32 



Bottom Water Temperature Characteristics 37 



Salinity Distribution in the Gulf of California 42 



General Circulation within the Gulf of California 43 



Descriptions of the Macro-invertebrate Assemblages and their environments. ... 47 



I. The Intertidal and Shallow Rocky Shore Assemblage 47 



n. Assemblage of Intertidal Sand Beaches and Sand Flats to 10 Meters. . . 48 



III. Low-Salinity Lagoon and Mangrove Flats Assemblage 52 



IV. Nearshore, Sand and Sand-Mud, 1 1-26 Meter Assemblage 53 



V. Intermediate Shelf Assemblage, 27 to 65 Meters 60 



VI. Outer Shelf Assemblage, 66 to 126 Meters, Clay Bottom, Southern Gulf 

 of California 76 



1) Support for this study has been received from the National Science Foundation Grants 

 G-5419, G-13163 and G-20060, and funds from the Of^|jj^Naval Research, Nonr- 2216(01). 



2) Scripps Institution of Oceanography, Univen^i^^r7iarTi'|(teia, San Diego, also Universite- 

 tets Zoologiske Museum, Copenhagen, DenmaA. Presejj^addiUs: Systematics-Ecoiogy Pro- 

 gram, Marine Biological Laboratory, Woods^ole, Aj^Jj^usett^ 



1 Vidensk. Medd. fra Dansk naturh. Foren. fid. 126.i 



1939 



