NORTHUMBERLAND AND DURHAM. 125 



sixth of their length, a circumstance I have not ohserved in any 

 other species. The margin of the cell appears to be crenulated. 

 This character, however, is difficult to ascertain, I have watched 

 the opening of the cell several times when the polype was emerg- 

 ing from it, without being able to detect the exact form of the 

 margin, which is extremely thin and membranous. 



14. CAjMPANULARIA, Lamarch. 

 1. C. voLUBiLis, Linn. PI. IV., fig, 7. 



Stem creeping, sometimes giving off shoots in a free state, 

 generally spirally twisted: pedicles rather longish, spi- 

 rally twisted and not ringed at the base : a single spheri- 

 cal ring below each cell; cells generally rather narrow 

 and deep, with about ten shallow, blunt denticles round 

 the margin: ovicapsules rising on short pedicles from 

 the creeping stem, oblong flask-shaped, smooth, with a 

 long narrow neck. Height ^'otli inch, 



Sertularia voluhilis, Linn. Syst. Nat., 12th Ed. 1311. 

 Small climhing coralline ivith hell-shaped cups., Ellis. 

 Corall. 24, t. xiv., f. «, A. 

 On Plumidaria falcata, Sertularia fallax, and oihev zoophytes 

 from deep water ; frequent. 

 Three or four species have hitherto been confounded under the 

 name of Campanularia voluhilis. It is, therefore, necessary to re- 

 describe and discriminate them, and to ascertain, if possible, to 

 which the Linnsean appellation properly belongs. Unfortunately 

 the description of that author is very imperfect ; but as he quotes 

 the excellent figures of Ellis, with which his description, as far 

 as it goes, corresponds, these may fairly be taken as representing 

 the true C. voluhilis. The distinguishing character of the species 

 there represented is the spirally twisted stem ; and Ellis remarks 

 in his description, " that at the bottom of each (cup), where they 

 join the stalk, the microscope discovers to us a very minute 

 spherule, or little ball, as in some drinking glasses." With these 

 characters the species here described perfectly agrees. I have for 

 some time been satisfied that this was distinct from the C. volu- 

 hilis of Johnston and other modern British authors, but it was 



