THE ACTINIA. 



571 



The term coral insect should now be abandoned. Yet we hear it used by persons who 

 ought to know better. The idea that the coral animal is a separate creature which builds 

 mechanically its blocks of coral, should be ignored, as the corals are, in most respects, the 

 same as the shells of clams or other shell-fish, merely the lime skeletons of the soft animal, 

 secreted, as our own bones are, for support to the soft parts. Thus, the corals are not anything 

 like insects, and they are very much lower in the scale of life than the insects. 



The genus Actinia includes a large number of soft-bodied creatures that do not secrete a 

 lime, or hard covering, but have instead a thick, leather-like exterior. This creature may, 

 for convenience, be compared to the naked mollusk, the garden-slug, while the coral, with its 

 lime tube around it, may be regarded as corresponding to the garden-slug that has a shell, the 

 garden-snail. This assumed analogy may help the reader to understand the subject. But, at 

 all events, it must be understood that the corals which we admire so much for beauty of form 

 and cells, are compound skeletons, which, like our bones, have been secreted by the animals 

 that are now dead and decomposed. Corals are difficult to understand. We may readily get 

 an idea of the corals that are made up of a congregation of stars, for each star is a sea-anemone, 

 Actinia, with its secreted skeleton around it. But when we are asked, how about the Mean- 

 drinas which have long, winding pits, we have to explain that the animals are compound, and 



GKKAT CRAMBACTIS. CrambacUs arabica. (A little diminished). 



mouths are seen at intervals. It must be remembered that these animal forms are so low in 

 the scale of life, it is not expected they will be found observing the strictest conventionalities. 



We have, on the New England coast, a species of Actinia (Metridium marginatum) that 

 grows to be about the size of a tea-cup. Its color is sometimes rather attractive, of a pinkish, 

 but usually rather sombre hue. It is a pleasing object in the aquarium. It is found in shady 

 pools among rocks at low water. Several beautiful forms are found in deep water. The 

 warmer waters of the tropics teem with gorgeous colored species. 



One example we remember as especially interesting, is a species that bears green, leaf- 

 shaped appendages between the tentacles. One only we obtained, while resident on the Reef at 

 Tortugas. This, or one very closely like it, is figured by Dana, in colors. It was about seven 

 inches in length, and three inches diameter. Its body was columnar and fluted, of a delicate 

 pinkish-white. Between the tentacles were organs that resembled oak-leaves, both in exquisite 

 outline and in color. It was a most beautiful object. We kept it in our sea aquarium, until 

 Mr. Barnum sent an agent to Tortugas for the purpose of gathering marine objects for his then 

 new aquarium in New York. This Actinia we sent to Mr. B., and it proved an especial 

 attraction for many months. 



