200 NATURAL HISTORY. 



discovered, although perfectly transparent, for if taken 

 up in a bucket full of water lentils, among -which they 

 are sure to be found, and placed in a glass vessel, they 

 always seek the side most strongly illuminated. They 

 are really nothing more than a membraneous sack, in- 

 closed at the lower end ; nevertheless, they crawl and 

 swim actively by agitating their long tentacles, and seize 

 small animals, from which they suck the fluids and 

 reject the remainder. If touched, they retract their 

 bodies so as to resemble a small mass of green jelly, and 

 when cut into pieces, each fragment becomes an entire 

 and perfect hydra. 



The Noble Coral (isis nobilis) is a stony substance 

 in the form of a stem, with branches of a beautiful red 

 color, and valued as an ornament ; most frequently found 

 in the Mediterranean. The little polypi are found in the 

 gelatinous stem which forms the axis of the stony one, 

 where, projecting their tentacles outside their cells, they 

 resemble buds or flowers. Thus grouped, they form tho 

 coral branches, and it is often observed that the polypi 

 on the lower portion of the trunk are dead whilst those 

 on the upper are living. 



The Sea Feather (pennatula rubra) looks much like 

 the common quill, measuring six inches, and has a mem- 

 braneous barrel on which these polypi rest, giving it the 

 appearance of a bearded feather. They have been termed 

 the gems of the sea. They fasten in the sand, and sparkle 

 even in the daylight as if surrounded by bright little 

 stars. 



The Sea Anemones (actinea coriacea) are round, and 

 resemble a flower; they attach themselves, by a broad 

 base or foot, to a rock, and have numerous tentacula 

 about the mouth, or upper extremity ; are about the size 



