1863.] DUNCAN WEST INDIAN CORALS. 457 



EXPLANATION OF PLATES XIII.-XVL, 



Elustrative of the Fossil Corals of the West Indies. 



Plate XIII. 

 Fig. 1. Astreea {Heliastraa, Edwards & Haime) crassolamellata : a, transverse 

 section of a corallite ; b, natural cast of a calice ; c, diagram of the 

 septal arrangement. 



-, var. nobilis : a, transverse section of a corallite ; b, dia- 



gram of the septa. 



3. , var. magnifica ; transverse section of a corallite. 



4. , var. magnetica ; transverse section of a corallite. 



5. , var. Nugenti ; transverse section of a corallite. 



6. , var. minor ; transverse section of a corallite. 



7. The primary septa of the various forms. 



8. Astraa {Heliastrcea, Edwards & Haime) Antiguensis ; the calice, mag- 



nified £ a diameter. 



9. ( ) costata ; transverse section of a corallite, magnified 3 dia- 

 meters. 



10. ( ) cellulosa ; transverse section of a corallite, magnified 6 



diameters. 



11. ( ) tenuis; transverse section of a corallite, magnified 3 dia- 

 meters. 



12. ( ) megalaxona : a, transverse section of part of a corallite, 



magnified 4 diameters ; b, transverse section of a cast of a corallite, 

 magnified 3 diameters. 



Plate XIV. 



Fig. 1 . Isastraa turbinata : a, transverse section of a corallite ; b, calice ; c, 

 longitudinal section of a corallite ; all magnified 2 diameters. 



2. conferta; transverse section of a corallite, magnified 4 dia- 

 meters. 



3. Stephanocoenia tenuis : a, part of corallum ; b, transverse section of 



corallite ; both magnified 5 diameters. 



4. Alveopora Dadalcea, var. regularis : a, transverse section of corallites ; 



b, longitudinal view ; c, same view of a cast ; all magnified 6 dia- 

 meters. 



5. microscopica ; transverse section, magnified 15 diameters. 



6. Astroria polygonalis ; transverse section of a cast, magnified 2 dia- 



meters. 



7. Astroc&nia ornata ; transverse section of part of a corallum, to illus- 



trate the thinning of the larger septa and the absorption of the 

 smaller during silicification, magnified 10 diameters. 



8. Coeloria dens-elephantis ; transverse section of the cast of a corallite, 



magnified 2 diameters. 



9. Astrma (Heliastraa, Edwards & Haime) endothecata, var. 1 ; trans- 



verse section of a corallite, magnified 2£ diameters. 



Plate XV. 



Fig. 1. Brachycyathus Henekeni; calice, magnified 4 diameters. 



2. Placotrochus Lonsdalei : a, lateral view of a corallite ; b, calice ; both 



magnified 4 diameters. 



3. Thysan us corbicula : a, lateral view of a corallite ; b, calice ; both 



magnified 2£ diameters. 



4. Barysmilia intermedia ; corallum. 



5. Dichocoenia tuberosa ; b, corallum, of the natural size ; a, calice, mag- 



nified 3 diameters. 



6. Astraa (Heliastraa, Edwards & Haime) Barbadensis : a, lateral view 



of corallum, magnified \ a diameter ; b, calice, magnified 3 diame- 

 ters ; c, two septal laminas, magnified 4 diameters. 



7. ( ) endothecata : a, lateral view of a corallite ; b, calice. 



8. ( ) cylindrica : lateral view of part of the corallum. 



VOL. XIX. — PART I. 2 I 



