SEA-SIDE STUDIES. 



317 



Coral assumes a variety of shapes, imitating almost all forms of 

 vegetation on the land. 



Most of the coral-producing polyps are confined to the tropical 

 parts of the ocean. A few kinds live in temperate waters. Dana's 

 Astrangia lives and flourishes in Long Island Sound, where it occurs 

 in little clusters upon stones and shells. 



The visitor to the sea-shore will hardly fail to find among the grow- 

 ing sea-weeds little^ plant-like clusters like the one represented by Fig. 9. 

 This is a cluster of hydroids, and its life-history is very interesting. 

 The beginner may well be pardoned if he mistake these little clusters 

 for plants, but they are indeed animals. From each little branch there 

 arise buds (Fig. 10), which enlarge, till at length they become detached, 

 float away, and grow into the beautiful jelly-fishes known as Sarsia 

 or Coryne ; it has been called by both names, the latter name mean- 

 ing a club, and the former coming from Sars, the distinguished Norwe- 

 gian naturalist, who was one of their earliest investigators. 



Other hydroids, called Campanularians, will be found among sea- 

 weeds. Here the minute jelly-fishes are formed in little bell-shaped 

 organs (Fig. 12). At length they drop out into the water and become 

 free jelly-fishes similar to Tiaropsis (Fig. 14). 



Fig. 12.— Campanularian {Obelia commisfiuralis, 

 McCready). The hydro-inediisie in the cups 

 drop out and become free Medusae, or jelly- 

 fishes, similar to Fig. 14. 



Fig. 14.— Campanitlarian (Tiaropsis 

 diademata, Agassiz). 



Fig. is.— Tiibidaria Contlboiii/i (Airassiz). 

 m, Modus* ; ct, coronal tentacles ; 

 p, proboscis. 



The visitor will find other hydroids, which appear like miniature 

 trees with all their foliage crowded to the top, and from beneath which 

 there hang bunches, as it were, of grapes or other fruit. Such is Tu- 



