434 NEW OR CRITICAIi BRITISH MARINE ALGiE. 



2. Hyella voluticola Chodat in Bull, de I'Herb. Boissier t. v. 

 No. 8 (August, 1897), p. 716. 



This species, which was found by M. Chodat on the coast of the 

 Isle of Man, is said to differ from Hyella ccesjntosa Born, et Fl. in 

 its pinkish-purple colour, a slight difference in the structure of the 

 sheath, the shorter branches, and the absence of true sporangia. 

 From M, Chodat's account of it there can be little or no doubt that 

 it is the same plant that I have called Hyella ccsspitosa var. vitida 

 (vide Journ. Bot. 1896, p. 385). More fortunate, however, than 

 M. Chodat, I observed on my specimens several true sporangia very 

 similar to those of Hyella caspitosa. With regard to the other 

 characters, the normal blue-green or greyish-purple colour of many 

 of the MyxophycecB under certain circumstances becomes rose-purple, 

 as in the wsiviety purp^uea of Calothrix confervicola. The length of 

 the branches in true Hyella caspitosa is very variable, and no re- 

 liance can be placed on the shortness of the branches as a specific 

 character. As to the differences in the structure of the sheath they 

 are at most but slight. Although, as I have already stated [Journ. 

 Bot. I.e.), I am not prepared to say that H. voluticola may not be 

 specifically distinct from H. caspitosa, I prefer, in the present state 

 of our knowledge, to regard it as a well-marked variety of the 

 earlier described species. 



3. Spieulina versicolor Cohn in Kabenh. Fl. Eur. Alg. vol. ii. 

 p. 292. First noticed by Mr. Brebner on the walls of tanks in the 

 Plymouth Marine Laboratory, but subsequently found by him on 

 the shores of the Barn Pool, forming thin layers on the surface of 

 the mud. Prof. Phillips informs me that he too has found the 

 same species at Bangor. 



4. Plectonema Nostocortjm Bornet in Born, et Thur. Notes 

 Alyologiques fasc. ii. p. 137. Endophytic in the gelatinous fronds 

 of Rivularia bullata, Torquay, E. A. B. 



Chlorophyce^. 



5. Ulvella fucicola Kosenv. var. globosa, nov. var. Fronds 

 minute, 90-400 p. in diameter, scattered, solitary or in groups of 

 twos or threes, globose or hemispherical, firm, smooth. Thallus 

 at first monostromatic, finally composed of three, four, or more 

 layers of cells. Cells 15-45 p long by 7-9 p wide. Chromatophores 

 and sporangia as in the typical form. Hab. : Epiphytic on the 

 filaments of Sphacelaria racemosa, Berwick, E. A. B. 



At first the fronds of this pretty little epiphyte are disc-shaped 

 and monostromatic, and so like those of Prinysheimia scutata that 

 it is not always easy to say to which species a specimen belongs. 

 The centre of the disc, however, soon becomes polystromatic, and 

 the fronds assume a more or less globular form, which is a marked 

 characteristic of the mature plant. These globose, bright grass- 

 green fronds are either solitary or collected into groups of three or 

 four individuals, and are either attached laterally to the filaments 

 of the host-plant, or entirely surround them. The variety differs 

 from the typical form in the thicker, more globular frond, slightly 



