80 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I49 



Table 4. — Grouping of seasonal stations into 13 grand stations. 



Grand Station 



stations > * > 



1 1 



2 2 33 32 84 96 126 



3 3 31 70 71 82 83 95 109 127 



4 4 30 69 81 93 94 108 128 



5 5 29 68 80 92 107 129 



6 6 28 66 79 91 106 130 



7 7 27 65 78 90 105 131 



8 8 26 64 77 89 104 132 



9 9 25 63 76 88 103 



10 10 24 62 75 87 102 133 



11 11 23 61 74 86 101 134 



12 12 22 60 73 100 135 



13 13 



Table 5. — Wilcoxon test on stations chosen at random in the E. advena zone in 

 March 1962 and June 1962. 



Total Living Population 



Mar. 1962 n = S . R m = 27 June 1962 n= l R m = 23 



111 = 5 m = 5 



Numbers of Living E. clavatum 



Mar. 1962 M = f R m = 24 June 1962 n ~ \ R m = 22 



m = 5 m = 5 



Numbers of Living B. frigida 



Mar. 1962 n = 5 c R m = 25 June 1962 n = l R m = 20 



m = 5 m = 5 



Numbers of Living E. advena 



Mar. 1962 n = { R m = 26 June 1962 n ~ 5 . R m -25 



m=5 m=5 



