INVERTEBRATE ANIMALS. 15 



fossil, 0. . The axis of the stem is either sub-calcareous, 



or made up of spiculse. 



U Examples of Verucella and Juncella, and a \evy 

 beautiful specimen of Paragorgia Johnsoni, 

 from Madeira, presented by its discoverer, 

 J. Yate Johnson. 



Group 43.— Section GOKGONACE^. Parti. Foliaceous. 

 Estimated number of species : recent, 25 ; British, 2. 

 ^ Phyllogorgia, in which the polype crust is 

 expanded, forming wings on each side of the 

 stem. RJiipidigorgla, or Sea-Fans, in which 

 the branches repeatedly unite, forming a net- 

 work. 



Group 44.— Section GORGONACE^. Part II. Arborescent. 

 Estimated numbei* of species : recent, 58 ; British, 2. 

 The base of the Gorgonla polype secretes the tough 

 horny elastic stem : another portion of the same polype 

 secretes the soft crust, or bark, which owes its beautiful 

 colour to the presence of calcareous spiculse. 



II Examples of most of the genera, many of them 

 from the " Argo " collection ; the larger fruticose 

 forms occupy the upper compartment. 



Group 45.— Section PBIMNOACE^. Trpvfxva, the poop of 

 a ship. On the coast of Norway Primnoa is said to 

 attain the height of fifty or sixty feet. Estimated 

 number of species : recent, 13 ; British, 1. 



IT Primnoa verticillata, from Madeira, presented by 

 J. S. Tyerman. Primnoa lepadifera. 



Family ALCYONID^. No solid central axis. 

 Group 46.— Sub-family TUBIPORINiE (Milne Edwards). 



