10 BRITISH FOSSIL CORALS. 
parts by a pellicular epitheca, which Mr. Searles Wood has designated by the name of 
periostracum, and presents some slight transverse folds. In the parts where the epitheca 
is worn off, the coste become visible. These are narrow, equal, closely set, and composed 
of a single series of indistinct, obtuse granule. The intercostal spaces present a series of 
small mural perforations, disposed with some regularity. None of the numerous specimens 
of this fossil which we have examined had the calice well preserved, and consequently 
we have not been able to ascertain as yet whether its margin is crenulated or entire, the 
fossula deep or shallow, and the columella projecting or not; but it is evident that the 
calice must be sub-circular, or slightly elliptic, with its two axes in the proportion of 
100: 120, and that the co/umella is spongy, not greatly developed, and spread in the 
direction of the long axis of the calice. 
The septa are well developed, and always form five cycla, but do not appear ever to 
constitute a sixth cyclum. The mode of arrangement of these lamin, which is charac- 
teristic in the family of Eupsammidz, is very evident in this species: the septa of the 
first four cycla are straight, but those of the fifth cyclum deviate a great deal from the 
direction of the radu of the circle represented by the calice, and are bent. In this last 
cyclum the septa of the sixth order are placed very close to the primary septa, and are 
united to them to a certain extent, near the wall, but diverge strongly from them as they 
advance towards the centre of the visceral chamber, and join the ternary septa near the 
columella; those of the seventh order are disposed in the same way near the secondary 
septa, and are also united to the ternary septa by their imner edge, but do not advance 
quite so near the centre of the visceral chamber ; the septa of the eighth and ninth orders, 
which complete the fifth cyclum, are smaller than the preceding ones, and are strongly 
bent, so as to join the septa of the sixth and seventh orders; and the septa of the fourth 
and fifth orders, which constitute the fourth cyclum, remain free, and advance in the 
middle of the sort of irregularly circular depressed area, formed by the coalescence of the 
septa of the eighth and ninth orders with those of the sixth and seventh. All the septa 
are very closely set and thin, but the primary and secondary ones enlarge a little towards 
their inner edge, and are almost equally developed, so that the adult corallum assumes the 
appearance of having twelve septal systems instead of six, which is the real number. We 
must also add, that the laminz constituting all these septa are cribriform, and not very 
granulate. 
The length of this corallam is commonly about eight lines, but the imdividual repre- 
sented by fig. 3 is more than twice as tall, without being broader than usual. The calice 
is in general about seven or eight lines broad in one direction, and six lines in the other. 
The greater development of the epitheca might suffice to distinguish Balanophyllia 
calyculus from all the other species belonging to the same genus, but it differs also from 
B. pralonga’ (a fossil species belonging to the Miocene deposits of Turin) by its broad basis, 
' Turbinolia prelonga, Michelin, Icon., pl. ix, fig. 1. 
