SOLID PARTS OF ANIMALS. 



manner, yielded the same constituents ; with this difference, that 

 no phosphate of lime could he detected in the fresh coralline, hut 

 the solution of burnt coralline yielded traces of it. The Iris ochra- 

 cea exhibits the same phenomena, and is formed of the same con- 

 stituents. When dissolved in weak nitric acid, its colouring mat- 

 ter falls in the state of a fine red powder, neither soluble in ni- 

 tric nor muriatic acid, nor changed by them : whereas the ting- 

 ing matter of the Tubipora musica is destroyed by these acids. The 

 branches of this iris are divided by a series of knots. These 

 knots are cartilaginous bodies connected together by a membra- 

 nous coat. Within this coat there is a conical cavity filled with 

 the earthy or coralline matter ; so that, in the recent state, the 

 branches of the iris are capable of considerable motion, the knots 

 answering the purpose of joints. 



When the Gorgonia nobilis, or red coral, is immersed in weak 

 nitric acid, its colouring matter is destroyed, an effervescence 

 takes place, and the calcareous part is dissolved. There remains 

 an external tubulated membrane of a yellow colour, inclosing a 

 transparent gelatinous substance. The solution yields only car- 

 bonate of lime : but when red coral is heated to redness, and 

 then dissolved, the solution yields a little phosphate of lime also. 

 Red coral is composed of two parts : an internal stem, composed 

 of gelatinous matter and carbonate of lime ; and an external 

 covering or cortex, consisting of membrane hardened by the cal- 

 careous salts, and both coloured by some unknown substance. 



The Gorgonia ceratophyta likewise consists of a stem and cor- 

 tex. The stem is composed of cartilage, hardened chiefly by 

 phosphate of lime ; and containing little carbonate of lime ; but 

 the cortex consists of membrane, hardened almost entirely by 

 carbonate of lime. The Gorgonia flabellum is almost exactly si- 

 milar. The cortex of the Gorgonia suberosa yielded gelatine to 

 boiling water ; when steeped in acids, it left a soft yellowish mem- 

 brane, and the acid had taken up a little phosphate and a large 

 portion of carbonate of lime. The stem contained scarcely any 

 earthy salt. When burnt, it left a little phosphate of lime. To 

 water it yielded a little gelatin; but it consisted chiefly of a 

 horny substance, analogous to coagulated albumen. The Gorgo- 

 nia setosa and pectinata exhibited the same phenomena, 



4. Gorgonia antiphates, like the other species of gorgonia, has 

 a horny stem, but it is destitute of a cortex. To boiling water 



