36 ZOOLOGY. 



A common species from the Indian Ocean and Red Sea. In this genus the 

 coralhim is formed bj a single polyp, which covers it beneath as well as 

 above. The tentacles are scattered, and when touched, are withdrawn 

 between the lamellse. 



Trihe 2. Caryophyllacea. 



Tentacles numerous, in two series ; coralla calcareous, cells multi radiate, 

 interstitial surface not lamello-striate. The fourth family is not coralligenous. 



Fam. 1. Cyatho2)hyllidcE. Interior middle of each corallum usually 

 transversely or obliquely cellular. 



Fa7n. 2. Caryophyllidoi. Tentacles crowded and long, mouths far 

 exserted ; interior of the corallum not transversely cellular, rays of the cells 

 more than twelve. Oeulina vii^ginea^ Linn. {pi. 75, fig. 58). White, 

 eighteen inches high, East and West Indies and the Mediterranean. 0. 

 geimnascerts {pi. 75, fig. 59). White, eight inches high. 



Fam. 3. Oemmiporidm. Tentacles short and marginal, in two or three 

 series ; disk broad, somewhat convex ; coralla porous, calicles with a thick 

 margin. ? Explanaria ananas {pi. 75, fig. 63). 



Fam. 4. Zoanthidce. Exterior subcoriaceous, tentacles short and 

 marginal, in two or three series. 



Tribe 3. Madreporacea. 



Tentacles in a single scries, seldom more than twelve, sometimes obsolete ; 

 coralla calcareous, cells small, six- to twelve-rayed, or obsolete ; interstitial 

 surface not lamello-striate. 



Fam. 1. Madreporidai. Tentacles twelve ; cells deep, extending to the 

 centre of the corallum, Madrepora pi^olifera {pi. 75, fi^. 60). 



Fam. 2. Favositidcß. Tentacles twelve ; lime secreted periodically at 

 base, so that the interior of the corallum is septate, rarely solid. Pocillopora 

 polytnarpha. {pi. 75, fig. 55). (Lamarck, 2, 311.) Red Sea. 



Fam. 3. Poritidm. Tentacles rarely more than twelve; base forming 

 porous calcareous secretions beneath ; coralla finely porous, cells shallow, 

 rays indistinct. Porites porites., Linn. {P. clavaria^ Blainv.) {pi. 75, 

 fig. 61). American and Indian seas. 



Tribe 4. Antipathacea. 



Animals six-tentaculate, base forming corneous secretions. 



Fam. 1. AntipatMdce. Animals fleshy, enveloping a corneous spinulous 

 axis. Antipathes spiralis {pi. 1^^ fig. 51); stem entire, long, and spiral, 

 about as thick as a quill, and attaining a length of sixteen feet. Indian 

 Ocean. 



Sub-order 2. Alcyonaria. 



Eight-tentaculate ; tentacles papillose, apex of the papillae perforate ; 

 often coralligenous. 



Tribe 1. Alcyonacea. 



Fam. 1. PennatulidcB. Free, or with the base sunk in the mud. 



Pennatula j^hosphorea, Linn. {pi. 75, fi^. 26). Bears some resemblance 



to a quill. It is found in the European seas, and emits a pale-blue 



phosphorescent light when disturbed. P. gramdosa^ Lam. {ßg. 25), and 



240 



