138 POPULAR HISTORY OP THE AQUARIUM. 



TUEBINALIA MILLETIANA. 



This is a very small Madrepore, shaped hke a top, with 

 ribs or plaits lengthways, but flattened at the sides. It 

 seems to present no point of attachment, and must there- 

 fore have a free set of plates within a moving animal, thereby 

 taking another step towards the Actinia. 



OcuLiNA PROLiFERA. — (Plate III. fig. 7.) 



Here we have a branched Coral, presenting a series of 

 radiating circles of plates united into one stem. Our figure 

 is from a small specimen in the British Museum ; but spe- 

 cimens of considerable size are procured occasionally, the 

 largest specimen weighing six pounds. It was first found 

 on the coasts of Norway. On British coasts it is rare, and 

 has not yet been taken in a living state. 



These are the British Corals. T\"e find that they are 

 bony skeletons of Actinia-like Zoophytes ; not made by 

 pincers and mandibles like wax honeycombs, but secreted 

 within the body of the animal in the same manner as our 

 bones are secreted within our own. It is the habit of the 

 Caryophyllece to live singly, not attached to each other, but 

 to independent bodies. The young generally separate en- 



