PROM THE ZONE OF AMMONITES RARICOSTATUS. 59 



epitheca, they are therefore not buds, but accidentally attached Corals. When more than 

 one Coral is attached to the same shell the bases appear to join. 



The calice is shallow, and its margin is formed by the epitheca, which often intrudes 

 upon its periphery ; it is circular or slightly deformed, and it may be either contracted or 

 very open. 



The septa are numerous and unequal ; they are irregular in size and in their arrange- 

 ment ; they are dentate, and the teeth are regular, rounded above, and ornamented with 

 waving lines and are largest near the axial space. The worn septa show their bases in 

 the form of oval swellings, and when these are of full size the appearance of a colu- 

 mella and pali is simulated. There are four perfect cycles of septa, and the fifth is very 

 irregularly developed, the higher orders being often rudimentary. In some large calices 

 the fifth cycle is complete. 



The endotheca is strong and well developed, audits dissepiments are numerous, oblique, 

 and arched. 



Height of Coral l/gths inch, 2 inches, l^ths inch, ^gths inch. 



Breadth of calice ^^ths inch, fgths inch, ^^ths inch, i^ths inch. 



Locality. Hippopodium-bed and Coral-bed of Marie Hill, Honeybourne, and Fenny 

 Compton. 



In the Collections of the Geological Society, British Museum, Dr. Wright, F.G.S., 

 Charles Moore, Esq., F.G.S., R. Tomes, Esq., and Rev. P. B. Brodie, F.G.S. 



The ornamentation of the teeth of the septa is very well seen in some specimens, but 

 usually it is worn off and the teeth also. The Coral, although very polymorphic, is very 

 easily distinguished from all others by its septa, epitheca, and base. 



2. MoNTLivALTiA MUCRONATA, Duncan. PI. XIV, figs. 4 — II and 14 — 16; PI. XV, 

 figs. 10—13. 



The corallum is very variable in shape ; it has a small peduncle, and a small and 

 more or less circular flat scar. The corallum is turbinate and symmetrical, and widely 

 open at the calice ; or more or less compressed and subturbinate ; or cylindrical and com- 

 pressed. When turbinate and with a circular calice, the calice is singularly shallow ; but 

 when cylindrical and compressed, or in the young state, the cahce is deeper. 



The epitheca is strong and rises up with the wall to produce a sharp margin to the 

 calice. The transverse markings are very distinct, and there are constricting ridges and 

 folds. The longitudinal markings are very distinct, ornamental, and symmetrical ; they 

 are in groups which are smallest at the base, where they are most distinct and rounded, 

 but they are less distinct at the calice where they are flat. The groups dichotomize, 

 so that there are usually 12 at the base and 24 at the calice; they are separated by 

 well-marked grooves and consist of bundles of longitudinal epitheca swellings and costse. 



The calice is either very shallow and circular, or deep and circular, or deep and 



