1 24 GOEGONIID^E. PART in. 



That state, however, is transitory ; for no sooner do they 

 lose their cilia and settle on a submarine substance 

 than their lower part becomes hard, forms a solid layer 

 on the substance, and constitutes the base for a Gorgon's 

 stem. A small elevation rises on it, and at the same 

 time the upper part of the larva assumes a fleshy consist- 

 ence and surrounds the elevation. These two grow 

 simultaneously ; the small elevation rises higher and 

 higher, and its coat containing the polypes grows pro- 

 portionally with it, and continues to cover it whatever 

 form it may take, whether a branching or plumage 

 stem, or a simple slender rod. The stem and branches 

 are increased in thickness by successive concentric 

 layers of horny or calcareous matter between their sur- 

 face and the soft bark. 



The Gorgoniidse are divided into three natural groups, 

 the Gorgons, Isidse, and Corallines, according to the 

 nature of their axis. The two first agree in having 

 stems either of a substance like cork or horn entirely 

 or partly flexible ; but the stem of the Gorgons has no 

 joints, while that of the Isidinse is jointed. The stem 

 of the Corallines has no joints, and is entirely stony and 

 branching. 



The Gorgonia verrucosa, so common in the Mediter- 

 ranean, British Channel, and the intermediate seas, is 

 like a small shrub a foot high, with numerous branches : 

 the cup-shaped tubercules inhabited by the polypes are 

 irregularly distributed, and not very salient, yet enough 

 to give the white encrusting coat a rough warty surface. 

 In this Gorgon there is an ovary at the base of each 

 polype: the eggs are discharged through eight small 

 pores placed between the bases of the eight tentacles. 

 These animals are wonderfully prolific: a Gorgon, six 

 inches high, produced ninety eggs in one hour. 



The Gorgonia graminea, found on the coast of Al- 

 giers, instead of being arborescent, is thin and cylin- 



