16 



ALLAN HANCOCK PACIFIC EXPEDITIONS 



VOL. 27 



AMPHIODIA URTICA COMMUNITY OF THE COASTAL SHELF 



< 

 o 

 o • 



546 



510 

 648 



444 

 465 

 436 

 383 

 420 

 356 

 297 

 252 

 203 

 389 

 285 



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s 

 o 

 o 



65 



74 



80 



68 



81 



63 



66 



57 



63 



69 



69 



59 



68 



59 



240 50 

 337 50 



315 

 274 

 191 

 188 



40 

 45 

 29 

 27 



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4859 



4935 

 5092 

 5354 

 5370 

 4757 

 5108 



4768 

 4924 

 4772 

 4878 

 5372 

 4920 

 4837 

 4-871 

 5255 



4835 

 5098 



4785 



4817 



Coefficient rank decreosing »• 



TOTALS of Coefficients l^gSSS^SlS^S^^ScD^S^gO- 

 for each sample = = 202229222205^200 SSSS 



Graph 9. The Amphiodia urtica community of the shelf of southern 

 California, represented by 20 of the samples having the dominant 

 most abundant, with paired coefficients of association and totals for 

 each sample. 



Another example is the Listriolobus community (Barnard and Hart- 

 man, 1959) of which 12 samples chosen for their extreme variability 

 are presented in Graph 10. Contrary to the Amphiodia community in 

 which dominance of Amphiodia in standing crop is also reflected in the 

 high frequency of individuals, the Listriolobus community is dominated 

 by a low number of individuals having a heavy bodyweight. Listrio- 

 lobus ranges in frequency from 1% to 8% of the specimens in a sam- 

 ple. A type-sample is 5419 in which Listriolobus represents 8% of the 

 specimens, Ceratocephala sp. (a specifically characteristic species) 

 9%, Saxicavella sp. (another indicator species) 16%, Callianassa sp. 



