CELLEPORIDjE I LEPRALIA. 313 



PLATE LV. FIG. 2, 3. 



Cellepora annulata, Fabr. Faun. Groenl. 436. no. 444. Turt. Gmel. iv. 641. Celle- 

 pora bimucronata, Lamour. Corall. 41. Lam. Anim. s. vert. 2de dit. ii. 260. 



Hob. On the fronds of Laminarise, common on the Ayrshire 

 coast, Rev. D. Landsborough. On shells of Limse dredged off Sana 

 Island, by G. C. Hyndman. 



Polypidom forming a small round or irregular calcareous crust, 

 entirely adnate, and of a clear or dusky white colour, according to 

 its age or state of preservation : cells not regularly serial, semi- 

 alternate, horizontal, contiguous, urceolate, the walls thickish and 

 punctured with holes situated in obscurely marked depressions which 

 cross the cell, and have given origin to its specific denomination ; and 

 there is a medial line down the cell apparent in good specimens. 

 The aperture is surrounded with a smooth rim, transverse, somewhat 

 bilabiate, the lips projecting a little in the centre ; and on the cen- 

 tral cells there are two obtuse spines, one on each side of the inferior 

 angles of the aperture, and shorter than its diameter. Ovaries glo- 

 bular, rather small. 



The cells are about the size of those of Lep. unicornis, but rather 

 broader in proportion to their length. The marginal, or new, cells 

 have seldom any spines, while the inner ones are almost as constantly 

 armed with them. It would appear, therefore, that their formation 

 is subsequent to that of the cell, and their presence not specifical. 



I entertain no doubt of this being the Cellepora annulata of the 

 most worthy author of the " Fauna Groenlandica." It were indeed 

 easy to point out discrepancies between his description and mine 

 which might determine others to a contrary conclusion ; but the en- 

 deavour to ascertain the species of the older authors will ever be 

 vain if we go to the work with an adverse or an unwilling mind. 

 The better way, surely, is to estimate fairly how far the differences 

 we may perceive may be accidental and peculiar to individual speci- 

 mens ; and to infer a probable identity where the essential and per- 

 manent characters are the same, or nearly so. Thus, in the example 

 before us, I find the proof of the sameness of our species in Fabricius' 

 admirable description of the aperture of the cell, and of its punctured 

 walls, so exact that it matters not that I have not found the cells 

 separate or solitary, as he appears mostly to have done.* The descrip- 

 tion of the aperture is as follows : " Osculum terminale marginatum, 



* Since this was written I have found the cells solitary in several instances ; and in 

 other examples there were only from three to five cells. 



