16 ANIMALS OF THE SEASHORE 



mens either new to science or not hitherto reported 

 in this part of the world. 



Sea animals, like the rest of the animal kingdom, 

 are divided into two main groups, vertebrates and in- 

 vertebrates. The vertebrates include those animals 

 that possess a backbone. In the sea this group is 

 represented by the fishes, whales, porpoises and a 

 few lesser known animals. The other group, the in- 

 vertebrates, includes the more primitive forms of 

 animal life. Although many species are very small, 

 the invertebrates comprise the great majority of the 

 inhabitants of the sea. These creatures, such as the 

 jelly-fish, starfish, crabs, the inhabitants of sea shells 

 and the like, make up the most conspicuous feature 

 of the animal life of the seashore. Even the most 

 casual visitor to the seacoast cannot help but observe 

 a few of the invertebrate animals of the region, even 

 if it be only on the dining room table. Moreover, 

 a great many visitors to the shore make collections 

 of the various shells, crabs, or other specimens that 

 they find washed upon the beach. It is with these 

 invertebrate animals that we shall be concerned in 

 this book. 



Various systems of classification of the inverte- 

 brate animals have been proposed. According to 

 the arrangement used here there are ten main divi- 

 sions or phyla, each one of which is discussed in a 

 separate chapter with the exception of the phylum 

 Arthropoda which is discussed in three chapters, 

 one dealing with the Crustacea (Crabs, Shrimp, 

 etc.), another with the Arachnoidea (Spiders, 

 King Crabs, etc.) and the third with the Insecta 

 (Insects). The various phyla are in turn divided 

 into smaller groups — classes, orders and families. 

 Only a few of the more important subdivisions are 



