TAB. III. 

 CORALS FROM THE LONDON CLAY. 

 TURBINOLIA DlXONII (p. 15). 



Fig. 1 . Adult specimen ; natural size. 



1 a. The same magnified, to show the characters furnished by the costae, and the 

 mural furrows. 



1 b. Vertical section, showing the columella, the lateral surface of the septa, the 

 wall, and the intercostal striae. 



1 c. Calice, magnified ; the numbers surrounding the septa indicate the cycla to 

 which each of these belong. 



1 d. Fragment of the wall in which the lamellar costse have been worn down, so 



as to show that the intercostal dimples are produced by transverse dissepi- 

 ments, and are not pores, perforating the wall. 



TURBINOLIA FREDERICIANA (p. 17). 



Fig. 2. Adult corallum ; natural size. 



2 a. The same, magnified. 



2 b. Calice, magnified. 



In one of the systems the septa are numbered with reference to the cycla to which 

 they belong. 



TURBINOLIA SULCATA (p. 13). 



Fig. 3. An adult corallum ; natural size. 



3 a. An individual showing a variety of forms. 

 3 b. The first of the preceding corals, magnified. 



3 c. Calice, magnified. 



TURBINOLIA HUMILIS (p. 18). 



Fig. 4. An adult specimen ; natural size. 



4 a. The same magnified. 



4 b. Calice, magnified. 



By a mistake of the artist, the third cyclum of septa is here represented as being 

 complete, whereas in reality these septa do not exist in two of the systems. 



TURBINOLIA PRESTWICHII (p. 20). 



Fig. 5. An adult specimen ; natural size. 



5 a. The same magnified. 



5 b. Calice, magnified. 



Leptocyatbus elegans (p. 21). 



Fig. 6. Side view of the corallum ; natural size. 



6 a. The same magnified. 



6 b. Under surface of the same, magnified. 



6 c. Calice, magnified;— 1, 1, 1,1,1, 1, Septa of the first order; 2, Septa of the 



second cyclum ; 3, Septa of the third cyclum ; 4, 5, Septa of the fourth 



and fifth orders constituting the fourth cyclum. 



