154 



CLASS-POLYPS. 



form to the whole animal structure ; or a quantity of earthy matter is deposited in this encrusting mass, and more or less solid 

 cavities produced in which 'the Polyps reside. 



Some Polyparies are fixed, that is, their stems are attached by broad bases or roots to some stone, rock, or other substance proportioned 

 to their size. But there are others which, although residing in a common fleshy substance overspreading a solid axis, are un- 

 attached, that is, the whole mass floats loosely in the water. Some of the Polyps, however, are not contained in or attached to 

 any polypary cavity, but are naked, gelatinous, independent animals, moving about at their own pleasure ; these are called Naked 

 Polyps. 



ILLUSTRATIVE EXAMPLES. 

 PLATE POLYPS. 



CORNICULARIA. Polypary fixed by the base, horny ; twigs simple, funnel- 

 shaped, erect, each containing a single polypus ; polypi solitary, terminal ; 

 mouth with eight pinnate tentacula, disposed in a single series. 



Illustration: Carnicularia rugosa. 



TUBIPORA. Polypary of rocky hardness, composed of cylindrical tubes, 

 straight, parallel, separate, but connected by external transverse collars ; 

 tubes jointed, and communicating by radiating and porous collars. This 

 polypary appears like a mass of minute organ-pipes banded together, and 

 hence its common name Organ Coral. 



Type of the genus, and 



Illustration : Tubipora musicalis. 



RENILLA. Body compound, free, flattened, kidney-shaped, pedicellate, 

 with one of its faces polypiferous, and with striated rays on the other ; 

 polyps with six rays. 



Type of the genus, Pennwttda remformis ; it inhabits the American 

 Ocean. 



Illustration : Renttta Americana. 



TUBULARIA. Polypary slender, tubular, horny, attached by its base ; 

 the extremities of its stem and branches each lodging a polyp; mouth 

 furnished with two rows of naked, non-retractile tentacules, pouched at the 

 root This genus of Polyps is marine. 



Illustration : Tubularia elytoidea. 



CORALLTOM. Polypary fixed, plant-shaped, not jointed, covered with a 

 cortical crust ; central stem, branched, stony, solid, striated on the surface ; 

 crust consisting of a soft fleshy substance, containing the polypi ; when 

 dried, porous and hardened ; cells scattered, eight-valved ; tentacula eight, 

 ciliated, and radiate at the mouth of the polypi. 



The only species of this genus is the /sis nobttis of Linnaeus, so well 

 known under the name of Red Coral (C. Rubrum), and which is manu- 

 factured into various ornaments. It is the production of the ocean in 

 general in warm climates. 



Illustration : Corattium rubrum. 



GORGONIA. Coral plamVlike, simple or branchy, branches sometimes 

 anastomising ; the axis longitudinally striated, hard, horny, and elastic ; 

 bark fleshy, and rarely chalky when dry ; often friable : polyps contractile. 



The genus contains many species, which have been divided into sections 

 by Lamarck. The first, with the cellules superficial, prominent, granular, 

 and tubercular ; and in the second the cells cylindrical, or lip-shaped, and 

 very prominent. 



The type of the genus and most common species is the Venus's Fan, 

 Gargania Flabettwn. 



Illustration : Gorgama patula. 



MlLLEPOEA. Stony, solid interiorly, polymorphous, branched or fron- 

 descent, furnished with simple pores, which are very minute, perpendicular 

 to the surface, and giving to them a finely-striated fracture. 



Type of the genus, M. camplanata, Lamarck. Two of the species are 

 natives of the coasts of Britain. 



Illustration : MUkpara spongitis. 



BICELLARIA. Polyparium of a cretaceous substance ; cells arranged in 

 two alternate rows, their orifices, on one face of the polyparium ; dichotomous, 

 fixed by radical fibres, plant-like ; polyps hydriform ; tentacula eight. 



Illustration: BiceUaria fastigiata. 



SERIALARIA. Polypiferous mass branched, horny, with slender fistulous 

 stems, furnished with cylindrical, parallel, adjacent, projecting cells, in 

 linear masses, sometimes separate and sometimes continuous. 



One species is found in the English seas, on fuci, below high-water mark. 



Type of the genus, and 



Illustration : Senalaria lengidera. 



CELLEPORA. This genus diners from the genus Mittepara, by having a 

 less stony structure, and being much less compact internally ; and from the 

 Fluctra in being less brittle, and having no flexibility. 



Illustration : Cellepara hyalina. 



LAOMEDIA. Coral flexible, branchy ; cellules stalked, scattered on the 

 stem and branches. 



Illustration : Laomedia cKchotama. 



PLUMULARIA. Stem not verticellated, horny, branched, with slender, 

 fistulous stalks ; cells sessile, uniformly distributed on one side of the 

 branch. 



Type of the genus, Sertularia pluma. 



Illustration : Plumularia secundaria. 



SERTULARIA. Polypiferous mass horny, with slender fistulous stems, 

 and furnished with separate lateral, tooth-shaped cells, the latter projecting, 

 alternate, usually with a joint above and below each ; vesicles larger than 

 the cells. 



Type of the genus, Serptda polygoruas. 



Illustration : Sertidaria pumila. 



CARYOPHYLLIA. Polypary stony, fixed ; the branches subturbinated, 

 longitudinally striated, each terminating in a cell composed of lamella?, 

 disposed in a stellated form. Body of animal elongated, and terminated 

 with eight feathery radiated tentacula. 



Illustration : CaryophyUia sditaria. 



MEANDRINA. Fixed, stony, forming a simple, convex, or hemispherical 

 mass ; surface convex, occupied by compartments more or less hollow, 

 sinuous, and furnished on each side with transverse parallel plates, which 

 adhere to the elevated crests. 



The type, M. labyrinthica, is found in the American seas. 



Illustrations : Meandrina limosa, M. Cerebriformis. 



ZOANTHUS. Body fleshy, somewhat cylindrical, club-like at top, slender 

 below, and attached by its base along a fleshy creeping tube, from whence 

 it originates ; mouth terminal, and surrounded with retractile radiating 

 tentacules. 



Illustration : Zoanthus Ellisii. 



ASTREA. Coral stony, fixed, conglomerate, encrusting other marine 

 bodies, or aggregated into a subglobose mass ; the upper surface only 

 covered with orbicular or subangular, lamellatud, sessile stars. 



Illustration : Astrea ananas. 



OCOLINA. Polypiferous mass stony, generally fixed, branching ; the 

 branches smooth, thick, and very short; some of the star-like mouths 

 terminal, the others lateral and superficial, spread over the surface. 



Type of the genus, Madrepora virginea; inhabits the Indian Ocean. 



Illustration : Ocuiina varicosa. 



ACTINEA. The several kinds of Sea Anemones, Actinice, are considered 

 to belong to the Polyps, of which they form the Fleshy Order ; their shap- 

 is that of a short hollow cylinder, highly contractile, the bottom or foot of 

 which is capable of fixing itself very firmly ; its sides are also contractile, 

 and have a coriaceous consistence ; a wide aperture on the upper surface 



