GENERA OF FA VOSITID^. 65 



size ; though I entertain no doubt as to the identity between 

 these and the siHcified specimens from the Corniferous Lime- 

 stone of the same region. As regards internal structure, the 

 walls of the corallites are comparatively thick, and the septa are 

 represented by a number (ten, twelve, or more) of blunt tuber- 

 cular ridges on the inner faces of the tubes (PI. III., fig. 2 c). 

 In silicified specimens, the tabulae generally appear to be 

 wanting (in their ordinary form), or are, at most, present as 

 incomplete transverse partitions ; but vertical sections of cal- 

 careous examples (PI. III., fig. 2 d) exhibit complete hori- 

 zontal or slightly flexuous tabulse of the ordinary type. All 

 the examples of this form, however, have the peculiarity that 

 the interior of the tubes is roughened by a series of close- 

 set projecting transverse ridges or lamellae, which are best 

 seen in silicified examples, in which the corallites are empty 

 (PI. III., fig. 2 e), but which can be recognised in thin vertical 

 sections of calcareous examples as short uneven lines occupy- 

 ing the interspaces between the regular tabulae (PI. III., fig. 

 2 d). These singular and characteristic structures are clearly 

 represented in the specimen of this form from Lake Erie 

 figured by Goldfuss under the name of F. basaltica (Petref 

 Germ., PI. XXVI., fig. 4 a). Mr Billings {loc. cit.), while 

 recognising the existence of these lamellae, regards them as 

 possibly merely the result of a peculiar method of fossilisation, 

 but I hardly think that there is any evidence to support this 

 view. Dr Rominger, if I rightly understand his views, regards 

 these projecting lamellae (or " squamae") as being an abnormal 

 form, or representative of the spiniform septa of so many of the 

 species of Favosites. In this view, for reasons previously given 

 in speaking of the genus, I cannot coincide. The transverse 

 position, and the often complete extension of these lamellae 

 across the whole diameter of a tube, are, in my opinion, fatal 

 to the idea that these structures are in any way of a septal 

 nature ; and I can only regard them as being essentially of the 

 nature of rudimentary tabula. The presence, then, of these 

 imperfect tabula:;, is characteristic of the present form ; but I 



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