DAILEY and PERRIN: HELMINTH PARASITES OF PORPOISES 



6p 

 4 - 

 2 - 

 OL- 



MONORYGMA 

 none infected 



I I I I I I I I I I I I 



14 

 12 

 10 

 8 

 6 

 4 

 ^ 2 



6 



c 



none infected 



I I I I I I I ' I I I I 



^ 16,- 



X 



12- 



10 



8 



6 



4 



2 







69% infected 



I I 



I I I I I I I I I I 



6p 



4 - 



100% infected 



:m 



lU] 



I I I I I 



II 



n 



1 10 20 30 40 50 60 



PHYLLOBOTHRIUM 



6 



4 - 

 2 





 14 

 12 

 10 



8 



6 



4 



2 







none infected 



NEONATALS 



I I I I I I I I I 



15% infected * 



CALVES 



r~i I I I I I I I I I i I I I 



I6p 

 14 

 12- 

 10 



8 



6 



4 



2 







58% infected 



SUBADULTS 



I I 



n I I I I I I I I I I I I I I 1 I 



6p 

 4- 

 2 







100% infected 



ADULTS 



JIL 



I I I 1 I I I I I ' I I I I 



Hj 



'Ol 10 20 30 40 50 60 70 80 90 100 



CYSTS (no.) 



Figure 15. — Frequency distributions of levels of infection by cysts of Monorygina 

 i^riDHildii and Phylohothrinni dclpliiiu in four age classes of Sicncllu gniffinani. 



Infection by cestode cysts showed the same 

 pattern as in S. graffniaHi, except that one 

 adult specimen was found to be free of Phijllo- 

 bothrium cysts. Also, as in S. graffmiud, calves 

 were most heavily infected with T. forsteri, and 

 Strobilocephalus triangularis was encountered 

 only in an immature specimen, a calf. 



ACKNOWLEDGMENTS 



The authors would like to express their 

 appreciation to Gerald Schmidt, University of 

 Northern Colorado; John Schacher, University 

 of California, Los Angeles; Mary Pritchard, 

 University of Nebraska; May Belle Chitwood, 



University of California, Davis; Kenneth S. 

 Norris, University of California, Los Angeles; 

 and Leo Margolis, Fisheries Research Board 

 of Canada, Nanaimo, for their help and advice 

 during the study. We would also like to give 

 special thanks to Barry L. Hill, Lorraine G. 

 Peterson, and Kenneth S. Raymond, for their 

 valuable technical contributions. Randolph Jose, 

 Ralston-Purina Corporation; Craig J. Orange, 

 Inter-American Tropical Tuna Commission; 

 and the captains and crews of the tuna vessels 

 Carol Virginia, Pacific Queen, Conquest. Mari- 

 etta, and Queen Mary helped us obtain jiorpoise 

 for dissection. Richard G. Van Gelder, American 

 Museum of Natural Histoiy; Donald R. Patten, 



467 



