M.Valenciennes on the Gorgonidse. 179 



the Gorgoni(2, and upon the form and arrangement of the cells in 

 the friable envelope of the branches, to which they give the name 

 of cortex. j\I. j\lilne-Ed\vards has ascertained that this enve- 

 lope, when examined upon living animals, is composed of a sort 

 of contractile parenchyma, which is rendered arenaceous by the 

 quantity of calcareous molecules contained in it. His extended 

 knowledge of the organization of the polypes, has shown him 

 the relations wliich exist between the envelope and the axis ; and 

 in order to render his idea more intelligible he has given the 

 name of sclerenchyma to the external portion from which the 

 extensible bodies of the polypes issue, and of sclerobase to the 

 concealed portion, wliich he still regarded as composed of a 

 horny matter. 



It appears from what I have just stated, that a Gorgonia is a 

 body formed by the union of numerous polypes upon a common 

 body, enveloped by an arenaceous sclerenchyma surrounding 

 another dendi'oid secretion, the sclerobase ; just as a VeretiUum 

 is composed of numerous polypes protruded from a soft fleshy 

 sclerenchyma. The sclerenchyma of the Gorgonidce contains 

 numerous sclerites. These, which are often microscopic, but are 

 sometimes as much as 3 millimetres in length and consequently 

 visible to the naked eye, occur in all the genera of this family. 

 The following are some of the principal forms : — 



1. The corpuscles have two small circles of tubercles at a 

 distance from one another on a short axis ; the tuberculate ex- 

 tremities resemble a small branch of cauliflower. These occur 

 in Junceella juncea, surculus and elongata, Gorgonella sulcifei-a, 

 Ctenocella pectinata, RJiipidigorgia umbraculum, cribnim, arenata, 

 &c., and in the common coral of the Mediterranean. 



2. Other sclerites are fusiform, with four or six cii-clets of 

 tubercles. These occur in Pterogorgia simplex, Plexaura virgea 

 and petechizans, Phijcogorgia fuliata, RJiipidigorgia reticulum, 

 Gorgonella cauliculus, &c. 



3. A third form is that of the clubbed sclerites, in which a 

 single extremity is dilated, and furnished with ridges, like some 

 ancient maces. These are found in Gorgonia crinita, papillifera 

 Q.ndi placomus, Gorgonella betulina and ceratophyta, Plexaura ho- 

 momalla, pensilis, parvula, &c. 



4. A fourth and new form is seen in the muricated sclerites 

 with four or several points, and entirely covered with spines, 

 which occur in Plexaura aurantiaca, Plexaurella dichotoma, Gor- 

 gonia vei-miculata, &c. 



5. A fifth form consists of larger or smaller scales, more or 

 less covered with small spines. These are found in Cricocella 

 verticillaris and plumat His, Primnoa lepadifera and antarctica, Gor- 

 gonia fungifei- a , &c. 



