COL UMNARIAD^E. 197 



Columnaria calicina, Nicholson. 

 (PI. X., figs. 2, 2 a.) 



Favistella calicina, Nicholson, Rep. Brit. Ass., 1874, and Second Rep. Pal. 



Out., p. 24, fig. 9, 1875. 

 Columnaria Hertzeri, Rominger, Foss. Cor. of Michigan, p. 90, 1876. 



Spec. Char. Corallum subhemispheric or pyriform, of 

 moderate but not very large dimensions. Corallites partially 

 in contact and partially more or less completely separate from 

 one another, averaging about two lines in diameter, but vary- 

 ing from less than a line up to three lines. Where the coral- 

 lites are more or less uniformly contiguous (as always towards 

 the base of the colony), they are prismatic or polygonal. In 

 diverging from the base, however, the tubes separate from one 

 another to a greater or less extent, so as to leave more or less 

 conspicuous intervals between them. In these portions of their 

 course each corallite is surrounded by a distinct and separate 

 wall, which is marked exteriorly by strong vertical ridges and 

 intervening grooves, about five of which occupy the space of 

 one line, together with fine encircling striae. Septa alternately 

 large and small, twenty-eight in number altogether, the prim- 

 ary ones being continued over the upper surfaces of the tabulae 

 to near the centre of the corallites, whilst the secondary ones 

 are marginal and rudimentary. Tabulae well developed and 

 complete, about three in the space of one line. Increase by 

 calicular gemmation, combined with parietal budding. 



Obs. This pretty little species is very distinct from C. alveo- 

 lata, Goldf., from which it may be readily separated by the 

 following characters : i. It is much more diminutive in aver- 

 age size than C. alveolata, its colonies rarely exceeding three 

 inches in diameter and two inches in height, and being often 

 much smaller than this. 2. The corallites are comparatively 

 lax and discrete in their mode of growth. Rarely they may 

 be more or less contiguous and prismatic in form throughout 

 the greater part of their course. More usually, they are cylin- 



