COELENTEKA — COEALS. 
51 
general Zoantliarian type, and are in multiples of (i. In Gallery X. 
many Palaeozoic corals they are in multiples of 4. The 
former have therefore been called Hexacoralla, and the 
latter, Tetracoralla. The wall of the Tetracoralla is often 
wrinkled, so tliat they have also been called Rugosa. 
Owinu: to the difficulties of classification, all the fossil Table-cases 
Anthozoa are placed togetlier and arranged under the chief ’^all-cases 
stratigra pineal divisions, the British and foreign specimens i 6. 
being separated as usual. 
Beffinning with the oldest, we find Ordovician corals Table-case 
from the Llandeilo rocks of Xortli ^^hlles and the Stinchar 
Limestone of Scotland. Strcptclasma belongs to the Zapliren- 
tidae ; Lyopora is allied to Favosites. These fossils are 
ill-preserved, and the genera will be better studied later. 
The British Silurian corals are maiidy from the AYen- Table-case 
lock Limestone. First come a number of genera placed in 
the family Favositidae, though not all with equal reason. 
Favosites, the honey-comb coral, itself consists of five- or six- 
sided tubes, set closely together ; each tube is divided by 
flat tabulae, and its cavity is in connection with that of its 
neighbours by small pores in the wall. Syrinyolites, a North 
American genus of the same age, has a similar structure, 
but its tabulae are funnel-shaped (Fig. 20). Some regard 
Fig. 20. — A Favositid Coral, Syringolites hiiroitensia, from the Silurian of 
North America, a, a fragment of a colony, natural size, b, a single 
calyx enlarged 8 diameters ; the tabula bears tubercles in radiating lines, 
like the beginnings of .septa, and is sharply bent downwards near the 
centre, c, a single tube split longitudinally and enlarged 0 diara. ; 
shows the funnel-shaped tabulae, d, a single tube seen from the 
outside and enlarged 6 diameters ; shows the mural pores that connect 
the cavities of adjoining corallites. (After Hinde.) 
these genera as related to Alveopora, a modern perforate 
madreporarian. Others compare them with SyTinf/opova, 
also shown in the Silurian series, but better studied in its 
