SERTULARIA. 133 
Hab. On old shells, from deep water. Aberdeen, Skene ; 
Angusshire, Don ; Seaton, J. Hogg ; Scarborough, Mr. Bean ; 
Dundee, W. Jackson, jun.; Firth of Forth, Dr. Jameson, 
Dr. Fleming, Dr. Coldstream; Cornwall, Mr. Couch; 
Giant’s Causeway, Mr. Hassall; on oyster-shells from Loch- 
ryan, D. L. 
Height two or three inches; stems erect, the stem and 
branches composed of closely agglutinated tubes; cells 
short and narrow; vesicles large, numerous, rough with 
spinous ridges. See the figure of it in Dr. Johnston’s work, 
plate ix. fig. 3, 4. 
Genus IX. SERTULARIA, Linnaeus. 
Gen. Char. Polypidom growing in the shape of a plant, and 
fixed by its base, variously branched, the divisions or branches 
formed of a single tube denticulated or serrated with the cells, 
and jointed at regular intervals: cells alternate or paired, bi- 
serial, sessile, urceolate, short, with everted apertures: ovarian 
vesicles scattered. Polypes hydraform.— Dr. Johnston. 
* Cells alternate, one to each internode. 
1. SerruLaria Potyzonias, Great Tooth Coralline, James 
Newton. (Plate IV. fig. 10.) 
i 
