ALCYONIUM. PENNATULA. 521 



nature of the surface on which it grows. Sometimes it spreads 

 out into finger-like projections ; and hence has received from the 

 fishermen the name of Dead-man s-hand. Other species attach 

 themselves to rocks, and grow, like sponges, hanging down from 

 the upper surface of submarine hollows in the face of overhanging 

 cliffs. Others of still firmer texture stand erect beneath the 

 shallow waters of the shore. Of this kind one of the most 

 remarkable species, probably the largest Alcyonium at present 

 existing, is the A.poculum, or Neptune's cup, which was disco- 

 vered by Sir Stamford Raffles upon the Coral reefs that sur- 

 round the Island of Sumatra. Many specimens, brought from 

 the neighbourhood of Singapore, now exist in the Museums of 

 this country ; and among these, some have attained the dimen- 

 sions of nearly three feet in height, and eighteen inches in 

 diameter. Their affinity with the Sponges is drawn yet closer, 

 by the siliceous character of the crystalline deposits, to which 

 they owe their firmness ; and, by some Naturalists, this species 

 has actually been referred to the class Porifera. 



1093. In the one family of this Order, the polypidom is 

 unattached ; and the animals are carried about by the action of 

 the waves, having but little power even of directing their move- 

 ments. Of this group, the Pennatula, or Sea-pen, is a charac- 



Fio. 622. PENNATULA. 



teristic example. It consists of an axis which is stony for a 

 considerable part of its length, but is flexible at its two extre- 

 mities. This is clothed with a flesh, which extends along the 

 sides into pen-like prolongations, arranged like the barbs of a 

 feather ; and one edge of each of these is fringed by Polypes. 

 The skin contains a large amount of calcareous spicula, and is 



