Ulvacea.'] enteeomoepha. 327 



Hab. In the sea, and also in brackisli and fresli- water 

 ditches. Annual. Summer. Common. 



It varies in length and breadth; sometimes short and 

 narrow, at other times two feet long and three inches in 

 diameter. It is always simple, whereas U. com_pressa is 

 branched. It changes from pale green to yellow, and be- 

 comes white in decay. 



The most interesting specimens I ever got of this plant 

 might be regarded as subfossil. They were found in a sand- 

 stone quarry at Ardeer, Ayrshire, about a mile from the sea. 

 When the quarriers had removed about six feet of earth, 

 they came to a thick stratum of shale, which was perforated 

 in many places, and in the mouth of the bore, which was 

 about an inch in diameter, I generally found a pretty entire 

 specimen of P/wlas crisjpata, the very same kind of mollusk 

 that I had often seen boring the shale in the sea at Salt- 

 coats. The perforation was about six inches deep, and 

 at the bottom of the bore there was in all cases a matted 

 pellet of vegetable substance. On macerating this, it 

 spread, and I saw by its puckerings "^ and reticulations that 

 it was EriteromorpJia intestiualis. I sent it to Sir William 

 Hooker, and he said that it was correctly named. See a fine 

 figure of tliis plant in ' Phycologia Britannica,^ PI. cliv. 



