used in the preparation of marine-sauce or Laver. The subject 
of our present plate is the more beautiful of the two, bemg 
commonly of a much brighter colour than its congener, but like 
it, the brilliancy varies according to the forwardness of the 
fructification. 
It will be seen, by reference to the plate, and synonyms 
quoted, that I propose to reduce the P. dinearis of British 
authors to its original place as a narrow variety of P. vulgaris. 
It was originally separated by Dr. Greville in his Algee Britan- 
nice, and this separation has been adopted in subsequent British 
works, though in the Manual I have expressed doubts of the 
validity of the supposed new species. When gathered in early 
winter, as in the month of November, it appears sufficiently 
distinct. Wide spaces of rock will be found clothed with 
narrow purple ribbons, as flat and free from undulations and as 
ovate at the base, with as distinct a stipes as are represented in 
figures 2 and 3. But two or three months later a considerable 
change will have taken place in the plants, their margins will be 
more uneven and their bases less ovate; and by the end of 
spring, it will be difficult to trace in the plants which will then 
cover the rocks the slender ribbons of winter. I admit that 
there are localities, very near high-water mark, where the frond 
never attains any great length or breadth, and therefore remains 
more true to the name /izearis, but this stunted growth 1s clearly 
referable to deficient nourishment. Where the plant grows in 
deeper water the fronds gradually develope into the broad state 
represented at fig. 1. This figure represents but a small 
specimen ; the frond is often two feet in length. 
Tam not acquamted with P. amethystea, Kitz., founded on 
a specimen collected by Mr. Shuttleworth on the Irish coast. 
Can it be merely a state of P. vulgaris? 
Vig. 1. Porpnyra vuLGARis. 2. Narrow state of the same, the P. linearis 
of authors ;—doth of the natural size. 3. Base of young frond. 4, Portion 
of surface, in fruit. 5. Vertical section of frond. 6. Tetraspore. 
