PLATE 17, 18. 
the dissepiments radiated with numerous, undulated strias. 
Each tube, where it passes through the dissepiment,! forms 
the centre to a star of these striae, which are extended, 
until they meet and unite with the radiations from the sur- 
rounding tubes. 
Rare ; the specimen figured, from Winster. 
I have classed this coral with the Tubiporce, but am doubt- 
ful if I am right in so doing. In its external form, the fossil 
very much resembles some of the recent Madrepores, parti- 
cularly the Madrepora musicalis, to which indeed it seems 
nearly allied, though unquestionably a distinct species. I 
have never been able, however, to trace in the tubes the 
least appearance of the stellated lammellae, which characte- 
rize the Madreporez: and should the species hereafter be 
found to possess such a structure, it will still be distinguish- 
able from others in that genus, by the radiations of the dis- 
sepiments. 
Fig. 2. Exhibits a specimen of this petrifaction. 
3. The same in a different position; showing the upper 
dissepiment. This specimen consists of chert and quartz. 
Its surface is somewhat drusy, or set with minute quartz 
crystals, scarcely to be expressed by a drawing. Between 
the tubes, lie a number of irregular, porous bodies, about 
the size of a nut, or smaller, perfectly detached from the 
