396 TORREY 



fragmentation, by making haphazard observations in various locaHties 

 upon thousands of polyps. Even though the precentages obtained are 

 only approximate, they give little support to the view that the brown 

 is the fundamental type. 



Nor is the evidence gathered in a special search for polyps showing 

 color transitions any more favorable. Only five such cases were 

 found. One was a muddy lavender blotched with orange, another 

 was a faded salmon spotted with brown, and three were dark brown 

 striped with orange. While these may have been changing their color, 

 it is not evident that all were originally brown, nor is it any more 

 probable that such an inconspicuous process could have any marked 

 effect upon the species as a whole. All were found within a few feet 

 of each other under a float in Oakland Harbor, where the water was 

 dirty and polluted with sewage. In the same place there were small 

 percentages of muddy lavender and pale orange polyps. These were 

 quite absent under a railroad mole some miles away, where the water 

 was much cleaner and better aerated, while the three main color types 

 flourished. For these reasons I am disposed to believe that conditions 

 of life effect certain minor transformations in the color of Metridium^ 

 though it does not seem to me that the three conspicuous types are 

 resultants of such a process. 



I have said that errors might be introduced into a study of variation 

 of Aletridium by disregarding its power of multiplication by basal 

 fragmentation. This method of reproduction is not uncommon among 

 anemones, particularly Sagartids. It was noted more than a century 

 ago by Abbe Dicquemare in the course of his observations on M. 

 dianthus^ and has been noted many times since. Andres, in 188 1, 

 gave a complete description of it, for two species of Aiptasia and 

 one Bunodes. It is the main cause, I feel sure, of the patches of 

 polyps of the same color which are noticeable wherever Aletridium is 

 abundant. These first attracted my attention in Oakland Harbor, 

 where the phenomenon was exceedingly striking. There the anemones 

 were wont to attach themselves to the piles supporting the wharves 

 and bridges. It was not an unusual sight to see one pile covered com- 

 pletely for several feet of its length with white poI}ps only, while 

 the adjacent pile might be as exclusively devoted to brown or orange. 

 Parker, in 1S99, accounted for a similar state of affairs at Salem, Mass., 

 on this basis. The same explanation applies to the case cited by Gosse, 

 in 1S60, and mentioned by McMurrich, in 1901, of the board, on one 

 side of which all the polyps were white, on the other, orange. Any 

 one may obtain strong evidence that this is the real explanation by 



