164 



THE OCEAN WORLD. 



divided into a series of stages or stories, by perfect diaphragms or 

 plates placed transversely, the plates depending from the walls and 

 forming perfect horizontal divisions, extending from one wall of the 

 general cavity to the other. In order that the reader may form some 

 idea of the Tabulate Madrepores, one of the polyps known as 

 millepores is here represented. The millepores were first separated 

 from the madrepores by Linnaeus, along with a great number of 



Fig. 79. Millepora alcicornis (Linn.), one-fourth natural size. 



species distinguished by the minuteness of their pores or polypiferous 

 cells (Fig. 79), represented above, as nearly allied, and perhaps 

 identical with Dr. Johnston's Cellepora cervicornis, a species found 

 in deep water on the Devonshire and Cornwall coasts, and, indeed, all 

 round our west coast. "A single specimen of this millepore is 

 about three inches in height," says Dr. Johnston, "and somewhat 

 more in breadth. It rises from a broad flattened base, and begins 

 immediately to expand and divide into kneed branches or broad seg- 

 ments, many of which anastomose, so as to form arches and imperfect 



