VORAL POLYPS. 



79 



lives in deeper water. Its young, however, is at an early 

 stage of its existence a free-swimming polyp, which was 

 originally described as an adult animal under the name of 

 Arar/iiHtctitt. In Zoanfh-iix the tegument is tough and. 

 leathery, and the different polyps are con- 

 nected by stolons. Epizoanthus americanus 

 Verrill lives in deep water, off the coast of 

 New Jersey and Southern New England, in 

 about twenty fathoms. Cerianthus, a gigantic 

 form, a native species of which (C. borealis 

 Verrill) lives at the depth of one hundred 

 fathoms in the Gulf of Maine deeply sunken 

 in the mud, where it secretes a shiny leathery 

 tube, is perforated at the end of the body ; 

 the young of a corresponding European 

 species is also free-swimming, like the young 

 Edwardsia. 



The coral polyps differ from the Actinoids 

 in secreting in the mesoderm a limestone 

 base, from which arise in the Zoantharian 

 corals stony septa serving as a support to the 

 animal ; these septa are deposited or secreted 

 in the chambers, so that in the coral polyp 

 there are soft partitions alternating with the 

 limestone ones, the latter formed at the base 



, . , ,.,. ., . Fig. 52. Hal- 



of the polyp, not completely filling the inter- campa producta. 



-V , , -After Verrill. 



meson terial chambers. 



Order 1. Zoanflmna. We will now enumerate some of 

 the leading forms of the first order of Anthozoa, the Zoan- 

 tliaria, to which the sea-anemones and most of the stony 

 corals belong. The group is called by some recent authors 

 Hexacoralla, the number of primary chambers and tenta- 

 cles being six, the latter rounded, conical, or filiform. In 

 the simple cup-shaped corals, as Dcltocyatlius and (Jaryo- 

 pliyllia, the coral forms a cup or t/teca, the lamellae which 

 arise from the base terminate in as many septa, the spaces 

 between which are termed lovuli. A central pillar or col- 

 umn formed by the union of the septa, or arising indepen- 



