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THE AMERICAN NATURALIST [Vol. XLI 



extending to Great Britain, New Jersey and California. Myrio- 

 irichia filiformis and M. clavceformis have practically the same 

 range as the Cladostephus species. Ralfsia borneti and R. ver- 

 rucosa have a slightly more northern range on both sides of the 

 Atlantic. Phyllophora hrodioei and P. memhrayiifolia range from 

 France and New Jersey to Norway and Labrador. P olysiphonia 

 violacea and P. fibrillosa from Virginia to IMaine, from the Med- 

 iterranean to Scotland. P. harveyi and P. olneyi are American 

 species, or possibly varieties of the same species; they have the 

 same range as P. violacea and P. fibrillosa; wherever I found 

 one, I should expect to find the other. 



"I could keep on for some time in this way, but will give only 

 one more instance; that is a group of species in the genus Anti- 

 thamnion, one of the most beautiful of the red algse. On the 

 European coast A. plumula ranges from Morocco to Great Britain; 

 A. cruciata about the same; .4. floccosa from the English channel 

 to high arctic regions; A. horeale from the Faroes north; A, 

 pylaiswi from Norway north. On the American coast A. plumula 

 and A. cniciatum range from New Jersey to Cape Cod; A. floc- 

 cosum and A. horeale from Cape Cod to Greenland; A. pylaiswi 

 from Long Island Sound to Greenland; A. americanum from 

 New Jersey to Portland, Maine. On our Pacific coast A. floc- 

 cosum ranges from California to Alaska; yl. horeale from south- 

 ern Alaska to high arctic regions; A. pylaiscei from Washington 

 north. Now these are all so closely allied that Rosenvinge some 

 time ago proposed to unite them all under the older name, yl. 

 plumida. He is a man with a strong tendency toward uniting, 

 it is true, and has since concluded that A. cruciatum, and possibly 

 A. floccosum are distinct; but at any rate, this shows how closely 

 allied they are. 



"Some things about algje seem very much like supporting the 

 mutation theory; when the same species occurs in widely distant 



Dr. Evans, while lacking the opportunity to ])ay very extended 

 attention to the subject, has given me the iollowinw' indication 

 of the distributional conditions in Hepatica\ "One of the l)est 

 examples of a cognate pair of species is Ijpfolrjrunca cllipfirn 



