CORALS OF THE LONDON CLAY. 17 
cyclum of costs appearmg near the calice, and consisting in very short, prominent, thin: 
lines, most developed between the primary and the tertiary septa. Intercostal furrows 
rather narrow, but presenting very clearly a double row of small dimples. Calicular 
Jossula not deep. Columella cylindrical, prominent, and very slender in proportion to the 
size of the calice. Septa very thin, exsert, rather unequal, and forming six regularly- 
developed tertiary systems (fig. 34). No traces of a fourth cyclum of septa corresponding 
to the rudimentary costa of the fourth cyclum. The tertiary septa joining the primary 
ones very near the columella. ‘The lateral surfaces of all the septa presenting delicate 
granulations. Height two lines; diameter of the calice one line and a third. 
This species bears great resemblance to Zurbinolia Fredericiana ; it differs from it by 
the rmdimentary state of the fourth cyclum of cost, and by its slender, round columella. 
The existence of well-formed intercostal dimples distinguishes it from 7: minor, 7. costata, 
T. Prestwichii, and 7. firma; the coste are much less prominent than in 7. sulcata, 
and 7. Divonii, from which this Coral may also be distinguished by its form; the costae 
are thinner than in 7. pharetra and T. Divonii, and the complete development of its six 
systems of septa does not admit of its being confounded with 7. humilis. 
We have seen but one specimen of this species ; it was found at Barton, and belongs 
to the collection of the fossils of the London Clay formed by Mr. Frederick Edwards. We 
have dedicated it to our friend Mr. J. S. Bowerbank, whose active researches have much 
contributed to the extension of our knowledge relative to this portion of British 
paleontology. 
4. Turpinonta Frepericiana. ‘Tab. III, figs. 2, 2a, 2 4. 
Corallum of a regular conical form, not much elongated, and rather broad towards the 
calice. Coste numerous, forming four cycla, closely set, unequal, and projecting very 
little; the secondary ones beginning a little above those of the first cyclum, but very near 
the basis of the corallum, and being, as well as the former, much thicker near their lower 
end than higher up, where they become very delicate (fig. 2a). The tertiary costa begin 
also at a short distance from the basis, but those of the fourth cyclum appear only in the 
upper half of the corallum; they are also rather thinner than the others. The intercostal 
furrows very narrow, and not very deep; the mural dimples not very apparent, small, 
closely set, and forming towards the calice, if not from top to bottom, only a single series 
in each intercostal furrow. Calicular fossula very narrow and shallow. Columella thick, 
compressed, granulated, rising higher than the septa, and presenting well-marked pro- 
longations of the principal septa. Three cycla of septa, and no vestiges of a fourth 
cyclum corresponding to the quaternary cost (fig. 24). The septa are much like those 
of the two preceding species, but they are a little thicker, and not so exsert ; the primary 
ones are, as usual, narrower than the ‘secondary ones, and these reach higher up along the 
columella; the tertiary septa are small, and join the primary ones, but appear to be 
3 
