Nemastomea.'] catenella. 217 



spherical spores ; 2, solitary, oblong tetraspores immersed in 

 the periphery." — Harvey. — Generic name signifies a chain ^ in 

 allusion to the chain or necklace form of the frond. 



1. Catenella Opuntia, Greville. (Plate X. fig. 39 a, 

 frond with fructification, magnified ; h, plant, natural size.) 



Hab. On rocks within high- water mark. Perennial. 

 Not uncommon in England, Scotland, and Ireland. In 

 Scotland we have gathered it from the rocks at Ardrossan 

 in the west, and on the pier at Kessen ferry, in Eoss-shire, 

 near Inverness. 



This little plant, seen on the rocks, is rather insignificant, 

 like dwarf specimens of Chylocladia articulata, though more 

 lurid in colour ; neither does it make any great appearance 

 in Stackhouse's plate. There is a good figure of it in 

 Turner^s ^ Historia Pucornm,'' a still better in our plate, 

 with one of the kinds of fruit, and an excellent one in 

 PL Lxxxviii. of Phyc. Brit., wherein both kinds of fruit, 

 long unknown, are well represented. It has, however, to 

 Algologists been a very troublesome little fellow, pushing 

 its nose, like Paul Pry, into not a few of their genera. 

 Driven from one, it took shelter in another, till Dr. Greville, 

 in pity for its manifold sufferings under the alien act, gave 

 it a permanent abode. He says, in his admirable ^Algse 



