GREEN ALG^. 51 



make up the substance of the frond appear never to 

 be separated. This is the most widely distributed of 

 the species of this genus. It is found in all waters 

 rom the equator to the arctic circle, and beyond. It 

 is extremely slender at the base, but gradually 

 expands upwards. The branches come out mostly 

 near the bottom, are themselves commonly unbranched, 

 and are neither so wide nor so long as the fronds of 

 the last species. They mostly have blimt tops which 

 look as though they had been cut square off. Most 

 of my plants are three or four inches high, though 

 I have some but an inch, and some quite eight inches. 

 The color is a little darker green than the last, and 

 the substance thicker. The branched frond dis- 

 tinguishes this species from the last, and the simple 

 unbranched branches distinguishes it from the next. 



Enteromorpha clathrata, Grev. 



This is by far the most variable of our Enteromorphm. 

 It is more slender than E. compressa, or any typical 

 form of E. intestinalis. It is often so fine and hair- 

 like, that you will certainly think it a Cladophora. 

 But a careful look ' at it with your pocket lens will 

 show you that the stem and branches are not made 

 up of a strmg of single cells, placed end to end, as 

 in that genus. This plant is profusely branched, and 



