lxxx BRITISH POSSIL CORALS. 



2. Genus Pterogorgia. 

 Ehrenberg, Corall. des Rothen Meeres, p. 144, 1834; Dana, op. cit., p. 647, 1846. 



Differs from Gorgonia by the polypi being bifarious. 

 Typ. sp., Pterogorgia anceps, Ehrenb., loc. cit., p. 145. 



3. Genus Bebryce. 

 Philippi, Zoologesche Beobachtungen, in Arcbiv. fur Naturgescbichte, von Erichson, vol. viii, p. 35, 1842. 



Arborescent compound polypi, resembling Gorgonia by their corneous sclerobasis, but 

 differing from the preceding genera by not being retractile. 



Typ. sp., Bebryce mollis, Philippi, loc. cit. 



4. Genus Phyllogorgia. 



Differs from Gorgonia by the ccenenchyma not constituting a cylindrical sheath around 

 the ramifications of the sclerobasis, but extending between them so as to constitute large 

 foliaceous, frondiform laminae, the two surfaces of which are studded with the calices of 

 the individual polypi. 



Typ. sp., Phyllogorgia dilatata ; Gorgonia dilatata, Esper, Pflanz. Gorg. tab. xli. 



5. Genus Phycogorgia. 



Sclerobasis flabelliform, divided into digitated lobes, and composed of delicate corneous 

 fibres united into laminae, the two sides of which are covered with the ccenenchyma, 

 and densely studded with numerous non-prominent calices. 



Typ. sp., Phycogorgia fucata ; Gorgonia fucata, Valenciennes, Voyage de la Venus, tab. xi, fig. 2. 



6. Genus Muricea. 



Lamouroux, Exposit. Method, des Polyp, p. 36, 1821. 



Differs from Gorgonia by the calices being surrounded with imbricated squammula.', 

 but not supported on long, verruciform, moveable appendices, as in Primnoa. 



Typ. sp., Muricea spicifera, Lamouroux, op. cit., tab. lxxi, figs. 1, 2. 



7. Genus Primnoa. 



Lamouroux, Hist, des Polypiers Flexibles, p. 440, 1816. 



Differs from the preceding genus by the polypi constituting long verruciform subpedi- 

 culated appendices, which are capable of motion at their bases. 



