330 Descriptive Zoology. 



4. In addition to producing eggs, many multiply by bud- 

 ding, which often results in (5), 



5. Colonies, often showing marked division of labor 

 among the differentiated individuals, or zooids. 



6. The body consists of three layers: an ectoderm, and 

 endoderm, and a middle, supporting layer, called the meso- 

 glea. 



7. The ccelenterates are mostly marine. 



CLASSIFICATION OF CCELENTERATA. 



Class i. Hydrozoa ; examples, hydra and the hydroids- 



Class 2. Scyphozoa ; examples, most of the large jelly- 

 fishes. 



Class 3. Actinozoa ; examples, the sea anemones and 

 most stony corals. 



Class 4. Ctenophora, the " comb jellies." 



