the Marine Algm of the Firth of Forth. 451 



monly associated with Rhizoclonium ripariuvi. Entero- 

 morpha percursa lias been foimd in pools near high water in 

 this area, which also often shows an abundance of large 

 forms of Monostroma latissimum. Prasiola marina is a very 

 common plant at high-water level. It differs from Entero- 

 morpha intestinalis in not descending with it into deeper 

 water, where streamlets enter the estiiar}'. Porphyra laci- 

 niata is very common from Inchcolm eastwards. It forms 

 a well-marked characteristic on the steep and somewhat 

 bare rocks of the Bass and May Islands. It often presents 

 a torn appearance, and in exposed places is stunted in 

 growth. Porphyra vulgaris is also found, though it often 

 extends somewhat deeper. Pohjsiphonia fastigiata occurs, 

 but is especially confined to the lower margin of the belt, 

 while its lower limit is regulated by that of the Fuci, on 

 which it especially grows. Yarious OsciUatoricv (e.g., 0. 

 sululiformis, &c.) and Lynghycc (eg., L. aestuarii) are found 

 throughout this area ; whilst the Jlyriofrichicc are not unfre- 

 quent, especially from Inchkeith seawards (e.g., Myriotri- 

 chia clavaformis and M. fliformis), and are often found 

 associated with one another. Like those just noted, Dictyo- 

 siphon mesogloia is common in this belt in many places in 

 the more seaward parts ; and Ectocarpus siliculosiis, E. 

 Uttoralis^ E. sphcerophoriis, E. tomeniosus, E. hrachiatus, 

 &c., are abundant throughout the estuary. Fuciis canalicu- 

 latus is especially characteristic, occurring abundantly from 

 Inchcolm eastwards. Ceramium diaphanum and C. ruhrum 

 are still common in rock pools, but tend to decrease as they 

 ascend in position. Chrondus crispus, which is abundant 

 throughout the rest of the tidal zone, reaches the lowest 

 part of this belt, but is of stunted growth. Many Clado- 

 phora: occur, and Corallina officinalis is still present, though 

 smaller than in the Fucus zone. Ralfsia verrucosa and 

 Cruoria pellita form here firm and tough incrustations on 

 stones. Asperococcus echinaius occurs in clear shallow 

 pools, very often in company with Hcdidrys siliquosa, espe- 

 cially at the lower part of the belt. Bangia fusco-purpurea, 

 which in some seasons is badly represented, is also found 

 here from Caroline Park eastwards ; and Punciaria planta- 

 ginea occupies a position at the level of high tide on the 

 east side of the May Island. Where logs of wood have 



