756 



THE SEA-PEN. 



strange fashion. Its branches are composed of a number of strong joints, united i< 

 gether by horny rings, so that a certain amount of flexibility pervades its structun 

 Owing to this formation, it is sometimes called the HORN-PLANT or SEA-SHRUB, title 

 surviving from the time when all the corals were thought to be vegetables, and the ex 

 panded polypes to be their flowers. They are always fixed by a base, and grow likt ] 

 trees, with their branches upwards. It is worthy of notice, that the Gorgoniae are neve. 

 bushy, and, for the most part, have their branches in the same plane. 



IN this illustration we have examples of some very interesting species, some of which 

 are extremely beautiful. 



SEA-FINGER.- Alcyoalutn digltatutn. 



SEA-PEN. Pcnnatula grisea. 

 SEA-RUSH. Vlrgularla mirabllis. 



The SEA-PEN is so named because its whole form bears the most remarkable resem- 

 blance to a quill-feather, consisting of a central shaft, from which a double row of 

 " pinnae " is developed at right angles, bearing the polype on their upper margin. As 

 may be seen by the illustration, the whole form of this curious being is remarkably 

 graceful, and it really seems as if it had been modelled upon a quill-feather plucked 

 from the wing of some bird. 



The Sea-pen is never attached to solid substances, but remains quite free in the 

 ocean. It does not, however, swim, but is a helpless sort of being, and only kept in 

 its proper position by the base being thrust into the mud or sand at the bottom of 

 the sea. Some species of Sea-Pinnae are phosphorescent, and present a magnificent sight 

 in the darkness. It was once thought that the creature was able to swim by means of the 

 webs, or pinnae, which flapped like the fins of a fish, but it is now ascertained that 



