184 MADEEPORARIA. 



Table V.— THE SEPTAL FOEMULA. 



The septal formula which characterised the primitive calicle, probably as an inheritance from 

 Eupsammiid ancestors, is shown in the Diagram A, p. 21. Tliis persists in many forms ; in 

 others it is only traceable ; from others again it has entirely disappeared ; lastly, in many cases 

 we can have no information because the descriptions were made at a time when the formula, 

 which was only discovered during the progress of the present volume, was quite unknown. 



As a rule we may say that the septal formula can only persist in shallow calicles. In the 

 deep calicles it is naturally obscured by the fact that the growing walls carry up the peripheral 

 edges of the septa, while their central portions sink into the depths of the fossa. It is, how- 

 ever, occasionally seen in deep-calicled forms, e.g. in G-. Java Sea 1 and G. Maldioes 4-. 



A. Forms in which the Typical Formula persists. 

 (a) Easily seen. 



G. Great Barrier Reef 1. 



G. North- West Australia 2. 



G. North- West Australia 3. With occasionally parts of a fourth cycle. 



G. Nm-th-West Australia J/.. Slightly obscured by the large columellar tangle. 



G. Philippines 1. 



G. Cliina Sea 2. 



G. China Sea 5. 



G. Java Sea 1. 



G. Java Sea 2. 



G. Singapore 2. 



G. Ceylon 1. 



G. Maldives 1. 



G. Maldives 4- 



G. Maiiritius 1. 



G. Sind 1. 



G. Sind 2. N"o trace of the fourth cycle in spite of immense size of calicle. 



G. Persia 3. 



G. Persia If.. 



G. Egypt 3. 



G. Vicenza 7. 



G. Genoa 3. 



G. Genoa 5. 



G. Dax 3. 



G. Gironde 2. 



G. Paris Basin 4- 



G. Sussex 1. 



G. Hampshire 1. 



