163 



are more pyriform or fig-shaped, and furnished with much smaller 

 apertures than are those of S. pumila. In Sertularia gracilis the di- 

 ameter of the polype-cell is only the si^th of an inch, while in S. 

 pumila it is the xisth ; again, in the former species, the breadth of 

 the opening of the vesicle is but the T ^th of an inch, while in the 

 latter it is as much as the eVrd. The latter difference is particularly 

 constant, and, when taken in connexion with the great disparity in 

 the size of the two zoophytes, is quite sufficient to establish the claim 

 of Sertularia gracilis to rank as a distinct species. 



The differences indicated in the above description, are admirably 

 shown in the figures which illustrate this communication, and which 

 are drawn by means of the camera to the same scale.* 



Campanularia serpens. 



Char. — Polypidom encrusting, spreading; cells small, sessile, often 

 curved, with an even patulous rim ; root-like fibres obscure, 

 firmly attached to the object (often a Sertularia) upon which 

 the species is developed, and incapable of being detached and 

 exhibited in a separate form. 



Campanularia serpens, Hassall, Zool. No. 69, p. 2223. 



Capsularia serpens, Gray, List of British Radiate Animals, p. 151. 



Hab. Coast of Dublin, 1842, Hassall, on Sertularia abietina. 



Plate XXI., figure 4. 



This zoophyte bears much resemblance to Campanularia dumosa, 

 with which, as it appears to be by no means uncommon, it has pro- 

 bably been frequently confounded. It differs, however, from that 

 species, in the smaller size of the cells ; in that these are invaria- 

 ably sessile; and, above all, in the absence of distinct root-like 

 fibres, capable of being detached, and separately exhibited. 



* One only of these figures is given, that of Sertularia gracilis. 



