20 BRITISH FOSSIL CORALS. 
Turbinolia minor differs from 7. salcata, T. pharetra, T. Nystiana, T. Dixonit, 
T. Fredericiana, and T. humilis, by not having the intercostal furrows ornamented with a 
double row of dimples, a character which in these can always be ascertained with the aid 
of a good lens. The imperfect development of two of the systems of septa, and the 
apparent existence of only five systems which is thus produced, is also sufficient to 
distinguish 7. mznor from 7: costata, T. dispar, T. Prestwichii, and T. firma. 
This fossil has been found only in the London Clay, at Alum Bay, in the Isle of 
Wight. The specimen figured in this Monograph belongs to the cabinet of Mr. J. S. 
Bowerbank. 
7. Turpinouia Firma. ‘Tab. II, figs. 4, 4a, 44. 
Corallum subturbimate, and elongated ; narrow at the basis. Coste thick, obtuse, 
closely set, and prominent ; those of the first two cycla very broad below the under end of 
the tertiary ones. Intercostal furrows narrow, and presenting neither mural dimples nor 
well-marked lateral transverse flutings or costal crenations. — Co/wmella compressed, and not 
very large. Septa rather thin, delicately granulated, and forming three complete cycla ; 
the tertiary ones less developed than the secondary ones, and cemented to the primary 
ones at a small distance from the columella. Height three lines and a half; diameter of 
the calice, one line and a half. 
Turbinolia firma differs from 7. costata, T. dispar, T. Bowerbankii, and T. Fredericiana, 
by the non-existence of a fourth cyclum of more or less developed cost; from Z minor 
and 7. humilis, by the complete development of the tertiary septa in the six systems, and 
from 7. sulcata, T. pharetra, T. Nystiana, T. Divonii, and T. humilis, by the non-existence 
of dimples in the intercostal furrows. It resembles very much 7. Prestwichii, but differs 
from it by its general form and by its thick obtuse costz. 
We have as yet seen but one specimen of this species; it was found at Barton, and 
given to us by Mr. Dixon: unluckily the artist in whose hands it was placed im order to 
have it figured, has broken it so much that it is no longer recognisable. 
8. ‘Turpinomia Prestwicum. ‘Tab. III, figs. 5, 5a, 56. 
Corallum of a cylindroid form, much elongated, and very obtuse at the basis. Coste 
strong, rather thick, and very prominent, especially towards the basis; those of the third 
cyclum beginning much lower down than in most species (figs. 5 a), and contributing to form 
the convex star seen at the basis of the corallum (fig. 5 4). Some slight vestiges of a fourth 
cyclum of cost at the bottom of the mtercostal furrows near the calice. ‘These furrows 
very deep, becoming very narrow near the wall, and not presenting any mural dimples 
s 
