HARDWICKE'S SCIENCE-GOSSIP. ' 



53 





Fig. 24. Gorgonia pinnata, x 3. After Forbes. 



The Gorgoniadce have been classified under the 

 head Polypi/era by Lamarck, and are placed in 

 the sub-class Corallaria by Milne-Edwardes : our 

 own countryman, Dr. Johnston, in the work we 

 have cited, places them in the order Antlwzoa As- 

 teroida, where they occupy a place between the 

 Pennatulidce, or " sea-pens," and the Alcyonidce, or 

 " dead man's fingers." The popular name of " Sea- 

 fans " is given by fishermen to the flat-growing 

 species of Gorgonia, such as G.flabellum, sometimes 

 called "Venus's fan"; while the bushy-branched 

 varieties of the order are called by them "Sea- 

 shrubs." 



Ray, in his ".Wisdom of God in Creation," p. 77, 

 says, " Those plants that grow deepest in the sea all 

 generally grow flat in manner of a fan, and not with 

 branches on all sides like trees ; which is so con- 

 trived by the providence of nature, for that the 

 edges of them do in that posture with the most ease 

 cut the water flowing to and fro ; and should the 

 flat side be objected to the stream, it would soon be 

 turned edgewise by the force of it, because iu that 

 site it doth least resist the motion of water ; whereas, 

 did the branches of these plants grow round, they 

 would be thrown backward and forward every tide. 

 Nay, not only the herbaceous and woody submarine 

 plants, but also the lithophytes themselves, affect 

 this manner of growing, as I have observed in 

 various kinds of coral and pori." The term " litho- 

 phyte " is now applied to those animals only which 

 possess a hard, stony axis, generally composed of 

 carbonate of lime. The term keratophyte (.Kipag, 

 horn, and <j>vtov, plant) has been more recently 

 adopted for those with horny flexible stems, such as 

 the Sea-fans. Iu Isis Hippuris (fig. 31), the central 

 axis is alternately composed of horny and calcareous 

 substances, exhibiting masses of the latter united 

 at intervals by a flexible material, allowing the stem 

 to bend freely in Jevery direction : " The object of 

 such diversity in the texture of the polypary of the 

 Corallida will be at once apparent when we consider 

 the habits of the different species : the short and 

 stunted trunks of corallium, composed of hard and 

 brittle substance, are strong enough to resist the 

 injuries to which they are exposed ; but in the tall 

 and slender stems of Gorgonia m&Isis, such brittle- 

 ness would render them quite inadequate to occupy 

 the situations in which they are found, and the 

 weight of the waves falling upon their branches 

 would continually break in pieces and destroy them. 

 This simple modification, therefore, of the nature 

 of the secretions with which they build up the ske- 

 leton which supports them, allows them .to bend 

 under the passing waves, and secures them from 

 otherwise inevitable destruction." 



Erom the reticulated framework of the typical 

 fan of Gorgonia flabellum, we pass on to other forms, 

 in which by degrees all trace of outward resem- 

 blance to the popularly-named species is lost. The 

 general outline of Gorgonia placonms is flattish, its 

 branches are disposed in a dichotomous order, but 

 though they incline towards each other, they rarely 

 unite and form a network. Li Gorgonia verrucosa, 

 the most abundant of our British species, the 

 general outline is somewhat fan-shaped, but there 

 is no approach to reticulation. 



In Gorgonia pinnata (fig. 24) it requires a con- 

 siderable effort of the imagination to trace any 

 resemblance to a fan. 



In the French example Gorgone verticillaire 

 (fig. 26), in which the polypes are arranged round 



