304 PEOF. p. M. DUNCAN ON THE 



colliaes ; and in some there are none at all : the length of the 

 septo-costse differs greatly. 



Lophoseris cristata, Ellis and Solander, sp., and L. explanulata 

 Lamk., sp., may be taken as types of the crested and plain species. 

 In the first species the calices are on hoth sides of the laminated 

 corallum. The septa are not perforate, but are well developed 

 and sharply granular at the top and sides. 



The central fossa is deep, and the columella is essential, as it 

 springs from the base of the calice and is not formed by the 

 septal ends ; it is composed of tv.-o or three rods united here 

 and there by transverse synapticula. The septa of one calice 

 are continued over the rounded, united margins to the neigh- 

 bouring calices, and the interseptal loculi, rather deep near the 

 fossa, become shallower externally. There is a small septo-costa 

 between the larger ones, and it rests on the floor of the inter- 

 septal loculus which passes from the contiguous calices ; this 

 is bounded below by the tops of synapticula which are sometimes 

 distinctly separate, and at other times formed into a solid wall. 

 In rapidly growing calices the synapticula cau be seen from above ; 

 they are large, and do not relate in any way to granulations 

 which exist above them. There are spaces between the synap- 

 ticula, when seen from above, as in Fimgia. A section or frac- 

 ture, parallel to the septo-costae, shows rather tall synapticula, 

 some being vertical and straight, and either narrow or broad, and 

 others curved, short, and mostly low down. Occasionally a 

 growth unites the synapticula, which may be parallel or not. 

 "With age, however, a distinct wall is produced between the calices 

 and in the collines ; and it is partly formed by an original vertical 

 wall resembling a narrow synapticulum, and by the fusion of the 

 synapticular growths on either side of it into one mass. So that 

 in solid parts of the corallum the synapticula are not seen in 

 series of three or four on the floor of the shallow loculi, but 

 there is one convex mass. But as grovrth proceeds, traces of 

 new synapticula are seen above the mass of the wall. The 

 stout synapticula of the interseptal loculi are very different in 

 appearance to the transverse synapticula between the columellary 

 rods, which are comparatively thin ; but in some parts of the 

 calices there are thin synapticula. These are not dissepiments. 

 Near the edge of the corallum, where growth is most rapid and 

 the costse are long, often slightly sinuous, and highly granular, 

 the loculi are shalloAV, and there are no synapticula there; 



