Madrtpora abrotandides 

 istrcea pallida. 



MniMpora criM/ero. 

 Kchinopora itnduldta. 

 Mceandrina ce.rebriformis 



to the vast number of the animals, and the rapidity with which they increase, the groups 

 of Astraea often assume enormous dimensions ; and in the secondary and tertiary rocks 

 they frequently occur in such huge masses that whole rocks are composed of their 

 remains. 



In the right-hand lower corner is seen a figure of that remarkable coral which is 

 popularly called BEAIN-STONE or BRAIN-CORAL, because the convolutions into which the 

 corallium is moulded much resemble those of the human brain. 



The animals of this genus are always united together in long waved series, each 

 having a distinct mouth and series of very short tentacles. The cells are very shallow, 

 and the valleys formed by their union are separated from each other by distinct ridges. 

 The shape of this coral alters greatly with age, somewhat resembling the top-shells when 

 young, but becoming rounded above when adult. The Brain-coral is found in several of 

 the hot seas. 



AMONG the Asteriadae, as these creatures are called, in consequence of the star-like 

 appearance of the polype or animal, the OEGAN PIPE-CORAL is perhaps the most striking. 

 It forms, as far as is yet known, the only example of the group to which it belongs, and 

 which is called Tubuliporina, on account of the multiplied series of regular tubes from 

 which it is formed. Most persons are familiar with this beautiful coral, with its sets of 

 tubes arranged like the pipes of a church-organ, or the storied rows of basaltic columns of 

 the Giant Causeway. 



