368 MESSRS. H. A. WICHOLSOlf AlfTD E. ETHEEIDGE 



incrusting, but is attached to foreign bodies at one point ; and the 

 rest of the lower surface is covered with a strong wrinkled epitheca. 

 Corallites erect, from an eighth to a tenth of a line in diameter. 

 Calices opening upon the upper surface of the corallum, irregular 

 in shape and size, but upon the whole more or less hexagonal, 

 with thin walls, and wholly devoid of any trace of a septal appa- 

 ratus or of septal teeth. Mural pores apparently absent. Tabulae 

 numerous, complete. 



Most of our specimens of this form present the appearance 

 believed by Mr. Lonsdale to be characteristic of Qhcetetes — that a 

 rough fracture lays open the cavities of the corallites without ex- 

 posing their walls. In some cases, however, the fractured surface 

 shows the walls of the tubes ; and in these, as well as in longitu- 

 dinal sections, we have failed to detect any traces of mural pores. 

 We were at first sight disposed to regard the present species as a 

 variety of C. {Alveolites) depressus, !Flem., with which it agrees in 

 the size of the tubes. It is, however, suiSciently distinguished 

 by its constantly different jToyw* and mode of growth, as well as by 

 the fact, conclusively shown by thin transverse sections, that there 

 are no traces whatever of ridges or teeth-like processes within the 

 corallites. On the surface, the calices show a certain irregularity 

 in form and size, which, is not characteristic of the typical forms 

 of Choetetes, whilst they are often transversely elongated, as in C. 

 septosus and C. depressus. Horizontal sections, however, taken a 

 little below the surface, prove that the corallites are essentially 

 hexagonal in form. 



Formation and Locality. — Carboniferous Limestone series, 

 Charleston, Fife (abundant) ; Bathgate ; Ecclefechan (Calcife- 

 rous Sandstone). 



Group F. Alveolites Goldeussi, Billings. 



There still remain a number of forms which have been referred 

 to Alveolites, and the true affinities of which are still doubtful. 

 Many of these forms we have had no opportunity of sufficiently 

 examining ; and we merely wish to draw attention now to one or 

 two corals which offer some troublesome difficulties. If we take 

 A. suhoriicularis, Lam., as the type of the genus Alveolites, we have 

 already seen that the only essential point by which it can be sepa- 

 rated from Favosites is the presence of a vertical septal ridge — 

 three of these ridges existing in other allied forms. We have, 

 however, some corals (such as Alveolites Goldfiissi, Bill., and A. 



