132 HISTORY OF BRITISH ZOOPHYTES. 



1-i. Sertulariapilicula, rem Coralline, //?^r/5(>;«. (Plate 

 V. fig. 17.) 



Hab. On seaweeds, especially on the entangled roots of 

 Laminaria digitata ; Mr. "W. Thompson states that it seeuis 

 to be partial to bivalve shells on the coast of Ireland, and it 

 is also found on Fliistra. It is rare in the west of Scotland, 

 and is seldom found excej)t at the roots of L. digitata. It 

 is not common anywhere, thougli it is widely distributed. 



" Height about an inch ; branches alternate ; cells wide 

 at the base, contracted towards the orifice, which is slightly 

 tubular, with a wrinkle or depression, forming a shoulder on 

 the upper side ; vesicles ovate with a narrow base, and a con- 

 tracted subtubular orifice." [I)i\ Fleming.) " It sometimes 

 rises to the height of four inches ; the stem has a zigzag 

 ap])earance ; the cells are shaped like a Florence fiask. The 

 vesicles are represented by Ellis as pear-shaped, but they are 

 very seldom seen. The singularity of its waved stem, with 

 its erect, single, axillary cell at the insertion of the branches, 

 together with the single pair of cells on each part of the 

 stem that form the angles, make it a very distinct species 

 from any of tliis genus." {Ellis.) 



Though it bears some resemblance to a young specimen 

 of S. abietina, it may be easily distinguished, as Ellis has 



