36 ZOOLOGY. 



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

 corallum 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 The tentacles are scattered, and when touched, are withdrawn 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?. 



Tribe 2. Caryojyhyllacea. 



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

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



Fam. 1. Cyatliophyllidm. Interior middle of each corallum usually 

 transversely or obliquely cellular. 



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

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

 more than twelve. Oaiilina virginea^ Linn. {pi. TS, jig. 58). White, 

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

 gemmascens {pi. 75, jig. 59). White, eight inches high, 



Fanti. 3. Gemmijwridw. Tentacles short and marginal, in two or three 

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

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



Fani. 4. Zoanthidce. 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. 



Fam. 1. 3fadreporidce. Tentacles twelve ; cells deep, extending to the 

 centre of the corallum. Madrepora ])ii"ol')feTa {pjl. 75, jig. 60). 



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

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

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



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

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

 rays indistinct. Porites j^orites., Linn, {P. clavaria^ Blainv.) {2?l. 75, 

 jig. 61). American and Indian seas. 



Tribe 4. Antipathacea. 



Animals six-tentaculate, base forming corneous secretions. 



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

 axis. AntipatJics spiralis {pi. 75, jig. 51); stem entire, long, and spiral, 

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

 Ocean. 



SUB-OEDER 2. AlCYONAKIA. 



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. 



Pennatida p>hosph(>rea., Linn. {pi. 75, jig. 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. {jig. 25), and 



240 



