36 ZOOLOGY. 



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

 coraUum is formed by a single polyp, which covers it beneath as well as 

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 The tentacles are scattered, and when touched, are withdrawn 

 between the lamella?. 



Trihe 2. Caryophyllacea. 



Tentacles numerous, in two series ; coralla calcareous, cells multiradiate, 

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



Fam. 1. Cyatlio])liyllidc2. Interior middle of each corallum usually 

 transversely or obliquely cellular. 



Fam. 2. CaryojyhylUdce. Tentacles crowded and long, mouths far 

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

 more than twelve. Ociilina virginea., Linn. (^>Z. 75, fig. 58). White, 

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

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



Fam. 3. Gemimi])orida\ 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. Zoanthida. Exterior subcoriaceous, tentacles short and 

 marginal, in two or three series. 



Tribe 3. Madreporacea. 



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

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

 surface not lamello-striate. 



Fa7n. 1. Madreporidm. Tentacles twelve; cells deep, extending to the 

 centre of the corallum. Madrepora prolifera {pi. T5, fig. 60). 



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

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

 polymorplia {pi. 75, fig. 55). (Lamarck, 2, 311.) - Eed Sea. 



Fam. 3. Poritidm. Tentacles rarelv more than twelve: base forminoj 

 2)orous calcareous secretions beneath ; coralla finely porous, cells shallow, 

 i-ays indistinct. Porites porites.^ Linn. {P. clavaHa, Blainv.) {^jI. 75, 

 fig. 61). American and Indian seas. 



Tribe 4. Antipathacea. 



Animals six-tentaculate, base forming corneous secretions. 



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

 axis. Antipathes spiralis {pl. 75, fig. 51); stem entire, long, and spiral, 

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

 Ocean. 



SUB-ORDEK 2. AlCYONARIA. 



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

 often coralligenous. 



Tribe 1. Alcyonacea. 



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



Pennatida pliosphorea., Linn. {pl. 75, fig. 26). Bears some resemblance 



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



phosphorescent light when disturbed. P. granulosa.^ Lam. {fig. 25), and 



240 



