16 MARINE ANIMALS OF MASSACHUSETTS BAY. 



. (Halcampa albida Ac.) 



Strange to say, the Actiniae, which live in the mud, are 

 among the most beautifully colored of these animals. They 

 frequently prepare their home with some care, lining their hole 

 by means of the same secretions which give their slimy surface 

 to our common Actiniae, and thus forming a sort of tube, into 

 which they retire when alarmed. But if undis- 

 turbed, they may be seen at the open door of 

 their house with their many-colored disk and 

 mottled tentacles extending beyond the aperture, 

 and their mouth wide open, waiting for what the 

 tide may bring them. By the play of their ten- 

 tacles, they can always produce a current of 

 water about the mouth, by means of which food 

 passes into the stomach. We have said, that 

 these animals are very brightly colored, but the 

 little Halcampa (Fig. 15), belonging to our coast, 

 is not one of the brilliant ones. It is, on the 

 contrary, a small, insignificant Actinia, resem- 

 bling a worm, as it burrows its way through the 

 sand. It is of a pale yellowish color, with whitish warts on the 

 surface. 



MADREPORIANS. 



Astrangia. (Astrangia Dance AG.) 



IN Figure 16, we have the only species of coral growing 

 so far north as our latitude. Indeed, it hardly belongs in 

 this volume, since we have limited ourselves to the Radiates of 

 Massachusetts Bay, its northernmost boundary being some- 

 what to the south of Massachusetts Bay, about the shores of 

 Long Island, and on the islands of Martha's Vineyard Sound. 

 But we introduce it here, though it is not included under our 



Fig. 15. Halcampa albida; natural size. 



