SEASONAL INFECTIONS OF THE SNAIL, CERITHIDEA 



CALIFORNICA HALDEMAN, WITH 



LARVAL TREMATODES 



By 



W. E. Martin 



Allan Hanccxrk Foundation and Biology Department, 

 University of Southern California 



INTRODUCTION 



Although Cort, McMullen and Brackett (1937, 1939), Dubois 

 (1929), McCoy (1928), Rankin (1939), Sewell (1922), and Wesen- 

 berg-Lund (1934) have reported on seasonal trematode infections in 

 freshwater snails, only the work of Miller and Northup (1926) has 

 dealt with such seasonal infections in a species of marine snail. Therefore 

 it seemed advisable to increase our knowledge of seasonal trematode in- 

 fections of marine snails and particularly of a Californian species, since 

 Miller and Northup worked with Nassa obsolete collected in the vicinty 

 of Woods Hole, Massachusetts. 



Cerithidea californica Haldeman literally carpets the mud flats of 

 many southern Californian estuaries. This snail is a favorable host for 

 more than twenty species of trematodes which have been found by the 

 author at various times during the past six and one-half years. However, 

 the present study was limited to one year beginning November 1953 and 

 ending October 1954. Collections of at least 1000 snails were made at 

 or near the middle of each month. All collections were made from a small 

 pond on an island in Upper Newport Bay, California. This pond is con- 

 nected by a narrow outlet to the main channel of the Bay and therefore 



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