ALCYONARIA. 219 



compound corallurn, but they are unknown in a fossil con- 

 dition. In the Alcyonidce the skeleton consists simply of 

 calcareous spicules scattered in the soft parts, and the 

 family is almost, unknown in the fossil condition. A 

 species of Alcyonium, however, has been recognised in tjie 

 Pliocene (Red Crag) of Britain. In the Pennatulidce (the 

 " Sea-rods " and " Sea-pens "), besides detached spicules, 

 there is a skeleton in the form of a horny or calcareous rod, 

 supporting the soft colony. The Silurian genus Protovir- 

 gularia was believed to belong to the Pennatulidce, but it is 

 certainly not of this nature, and is probably a Graptolite. 

 The family has, indeed, no certain fossil representatives till 

 we reach the latest Secondary or earliest Tertiary deposits. 

 In the Pisolitic Limestone (late Cretaceous) of France, we 

 have the genus Pavonaria ; while Graphularia occurs in the 

 Eocene, and the Miocene Tertiary has yielded examples of 

 Graplmdaria, Virgularia, and Ccelographula. In the family 

 of the Gorgonidce (" Sea-shrubs ") there is a branched sclero- 

 basic corallum, the surface of which is grooved or sulcate. 

 The corallum may be horny or calcareous, or it may be 

 composed of alternating calcareous and corneous segments 

 (as in Isis and Mopsea}. The earliest representatives of the 

 Gforgonidce so far as we have any sufficient evidence 

 are found in deposits of the age of the Eocene Tertiary, the 

 genera Mopsea and Websteria occurring in the London clay. 

 The genus Coralliwn, embracing the living Eed Coral, has 

 been quoted from the Jurassic and Cretaceous, and un- 

 doubtedly occurs in the Miocene Tertiary ; and deposits of 

 the same age have yielded species of Isis, Gorgonia, and 

 Melitlma. 



So far as all the preceding forms are concerned, it will 

 be seen that the Alcyonaria, though widely distributed in 

 existing seas, are of little geological importance, and are, 

 moreover, comparatively of modern origin. Mr Moseley, 

 however, has shown that the living corals of the genus 

 Heliopora are truly referable to the Alcyonaria, and not to 

 the Zoantharia, in which they had been previously placed : 

 and he has further shown that the large and ancient group 

 of fossil corals of which Heliolites is the central type, is 



