MADREPORES. 



177 



but in every case they were unconnected with each other. Other 

 rays soon make their appearance between those first formed ; they 

 are mere calcareous specks at first, but afterwards increase in size. 

 The first union of rays is observed as a small calcareous rim at the 

 base of the polyp, which afterwards increases in height and diameter 

 with the age of the animal." 



The animals of this interesting polypidom are vividly described 

 by Dr. Coldstream, in a communication to Dr. Johnston, as he 

 observed them at Torquay : 



" When the soft parts are fully expanded," he says, " the appear- 



Fig. 61. Flabellum pavonium (Lesson). 



i. Seen from the side. 2. Upper surface, with its plates and median furrow. 

 3. Animal, with tentacles expanded. 



ance of the whole animal closely resembles an actinia. When shrunk, 

 they are almost entirely hid amongst the radiating plates. They are 

 found pendent," he adds, " from large boulders of sandstone, just at 

 low-water mark. Sometimes they are dredged from the middle of 

 the bay. Their colour varies considerably. I have seen the soft 

 parts white, yellowish, orange-brown, reddish, and of a fine apple- 

 green. The tentacula are usually paler." 



Species of this genus are sometimes dredged from great depths ; 

 Professor Travers dredged one in eighty fathoms, and Dr. Johnston 

 remarks that the existence of an animal so vividly coloured at so 

 great a depth is worthy of remark. " When taken/' says the pro- 

 fessor, " the animal was scarcely visible, being contracted ; when 

 expanded, the disk was conspicuously marked by two dentated 



