WORMS 



BURROWING in sand and mud, lying under stones and in 

 crevices of rocks, concealed in various kinds of tubular cases 

 which are free or attached to stones or shells, crawling over the 

 ground or seaweeds, swimming free or attached to other ani- 

 mals, is found in abundance a class of animals commonly known 

 as " worms," and generally regarded as repulsive creatures un- 

 worthy of attention. 



To the biologist, however, worms are among the most interest- 

 ing forms of lower animal life. The amateur collector, if he 

 stops to give them careful consideration, will probably find them 

 unexpectedly interesting, and will be surprised to find how many 

 varieties of them there are, and how different they are from his 

 preconceived notion of them. Worms are varied in structure, 

 their habits are strange, and their form and color often beautiful. 

 Although plentiful, they are not conspicuous, but are easily found 

 if search is made for them, and so large a class of shore animals 

 should not be passed by unnoticed. Unusual biological interest 

 is attached to this group because, in the different types, affinities 

 with other classes of animals are found, suggesting, perhaps, 

 connecting-links with higher organizations. They are the first 

 animals to show definite bilateral symmetry, or two similar sides, 

 and to carry the same part of the body always in front. Formerly 

 one division, called Vermes, comprised all the worms. To-day they 

 are separated into four divisions, or phyla. The most careless 

 observer easily recognizes the basis of separation, for the flat- 

 worms, the round- or threadworms, the wheel-like animalcules, 

 and the jointed worms have very obvious differences. The names 

 given the phyla express these distinctions, the termination 



163 



