14 



ALLAN HANCOCK PACIFIC EXPEDITIONS 



VOL. 27 



MALDANE 



€497 



68ZI 



3639 



3179 



3179 



BZI9 



3399 



3180 



6779 



7155 



6850 



4851 



7729 



7028 





6503 



2317 



7050 



6828 



2336 



7051 



6820 

 >043 

 4846 

 53 67 



LYSIPPE 

 •? ►< O * «o 



G -» 10 *« 

 <o "o o * 



<0 «4 K <0 





3 2 3 7 5 4 



0__3__3 I 0__2 



2__4^J 3 l_J_ 



6 6 4 5 6 



Anobothrus 



Pectinaria — 



CopitellQ 

 RBCtinario — 



Oentalium 

 Pectinorio— 



AnclstrosyJIis 



7730 

 6503 



Pectinaria 

 Lysippa 



Graph 8. Representative samples of the Maldane and Lysippe com- 

 munities of submarine canyons with paired coefficients of association 

 and comparison to typical samples of other communities. 



of Maldane as 6779, but sample 4851 is swamped with so many speci- 

 mens of other species that Maldane represents only 31.0% of the total 

 specimens in the sample. This method does not consider that 4851 may 

 be a climax sample with its full diversity whereas 6779 may be in an 

 early stage of succession. Nor does it take into account that the Maldane 

 community may be composed of numerous subcommunities, in a few 

 samples of which (such as 4851) all the submembers are represented, 

 whereas satellite samples may represent only minor members. 



An alternate method may be used, viz. : in two samples to be compared 

 the most diverse one is designated the "type," the less diverse, the 

 "satellite" ; percentage compositions of all species of the "satellite" are 

 calculated ; those same species in the type-sample also are extracted and 

 percentage compositions calculated ; then the two samples are compared 

 by summation of minimum compositional percentages. Here the rela- 

 tionship of the satellite sample is compared to that portion of the type- 

 sample that might be visualized as one of its subcommunal components. 

 Such a comparison is made for 4851 as the type and 6779 as the 

 satellite, both dominated by Maldane. The resultant index of association 



