114 TABULATE CORALS. 



mens. In some examples the corallites, though still retaining 

 their cylindrical form, are very nearly in contact to their 

 calices ; whereas in others the tubes become completely dis- 

 junct long before their mouths are reached. In all cases, 

 however, the corallites are in close contiguity in all the cen- 

 tral portions of the skeleton ; and here their walls are always 

 perforated by irregularly distributed mural pores, the condition 

 of parts being, therefore, precisely the same as in Favosites. 

 The walls of the corallites, though moderately stout, are not 

 thickened by a conspicuous deposit of sclerenchyma, as in 

 Pachypora; while the calices are rounded, and often slightly 

 oblique, smaller ones being intercalated among those of aver- 

 age dimensions. Dr Lindstrom has noticed the fact that the 

 calices are occasionally closed by an opercular growth ; and the 

 exterior of the wall in the free portions of the tubes exhibits 

 numerous fine encircling striae. Transverse sections (PI. VI., 

 fig. I a) show that the tubes in the centre of the corallum are 

 subpolygonal, with moderately thick walls, the lines of division 

 between them always remaining quite distinct. At the same 

 time, well-developed spiniform septa are brought into view. 

 Longitudinal sections (PI. VI., fig. i B) precisely resemble 

 those of a Favosites, exhibiting septa and mural pores, along 

 with well-developed complete tabulae, which may be horizontal, 

 or may be curved with their convexity downwards. 



Formation and Locality. — Upper Silurian, Gotland, Col/., Dr 

 Gustav Lindstrom. 



Genus Romingeria, Nicholson. 



Orienstedtia, Rominger, Fossil Corals of Michigan, p. 70, 1876. 

 [Non Qiienstedtia, Morris and Lycett, 1854.] 



Gen, Char. — Corallum lax, spreading ; resembling Aulopora 

 in its general appearance, but only attached basally, and free 

 throughout the greater part of its extent. Corallites cylindri- 

 cal, annulated, multiplying by lateral gemmation, and typically 

 producing new tubes in umbellate whorls or verticils, which 



