Vacoham. — Madreporaria. 



EXPLANATION OF PLATES. 



PLATE 1. 



Figs. 1, la, 16. Desmophyllum galapagense, sp. nov., p. 63. Fig. 1, upright 

 view of corallum, height, 15 ram. ; fig. la, calicular view, greater 

 diameter, 6.76 mm. ; fig. 1, view of the edge of the wall, X 4. 



Fig. 2. Madrepora galapagensis, sp. nov., p. 63. General view of a corallum, 

 natural size. 



