112 SEA MOSSES. 



years, and have never found it growing there. None 

 of my correspondents have reported it north of Cape 

 Cod. 



Cladostephus spongiosus, Ag. 



This plant diners from the last by its shorter habit ; 

 by being more irregularly branched, the branches 

 spreading more widely, and having a thick, clumsy, 

 rambling appearance, and by the branchlets being 

 longer, irregularly whorled, and clothing the frond 

 in a denser, spongier fleece. It is not at all unlikely 

 that intermediate forms might be found which should 

 connect the extremes, typical of these two species, in 

 a single graduated series. My European plants 

 appear decidedly more " spongy " than the American. 

 Its local habitat is the same as that of C. vei'ticillatus. 



Sub-Order.— ECTOCARPE&. 

 Genus.— ECTO CARPUS* Lyngd. 



According to Dr. Farlow's list, this genus, in our 

 American waters, includes fifteen species. Of those 



I have selected five of the most common for our 



study. These plants, like the Cladophorce in the 



green Algae, and the Callithamnia in the red, are 



of capillary or hair-like fineness, and like them are 



* Ectocarpus = External fruits. 



