•2(56 



NATURE STUDY IN SCHOOLS. 



into a fl;>at, beneath which, and attached to it, are the various polyp-like or- 

 ganisms. There are several sets of these. One set feeds for the colony and 

 is provided with powerful dart cells, one possesses reproduction functions 

 and still a third set propel the colony. Alternation of generation also occurs 

 in this species. 



ORDER IV. JELLY FISHES. 



Here we find some species of animals which reproduce without alterna- 

 tion of generation. Jelly fishes occur in abundance off our coast and vary in 



Fig. 137. 



A, Large Star. B, Tooth, C. Lancet C o.-al. 



size with different species. Some are only an inch or so in diameter while 

 some measure five feet in diameter and are provided with tentacles which are 

 often forty feet in length. These species sting severely, and swimmers have 

 been known to have become entangled in their folds, paralyzed and drowned. 

 In some of these forms are found alternation of geneiation. 



ORDER V. SEA AXEMON1ES. 



Among these are some of the most beautiful and varied forms of ani- 

 mal life which inhabit the oeean. 



The true anemonies are rarely compound and differ from the hydras in 

 having the stomach cavity suspended within the body cavity or attached to 

 it by folds of the lining membrane of the outer wall, known as messenaries. 

 See fig. 13.3, p. The tentacles are numerous and" hollow. Through these 



