SUB-ORDER ANTIPATHARIA. 



301 



very elaborate piece of coral lace, flat and wonderfully fragile, was got up from 2,000 fathoms in the 

 Indian Ocean, and described by Moseley as one of these. The branching Madrepores belong to a 

 second sub-family, and they are the most vigorous of the reef-builders, living on the outer edge of 

 the reef, and attaining great bulk. Some live in quieter water. 



The second family, the Poritida?, is composed of two sub-families : the Poritina?, with little or no 

 tissue between the corallites, which are tolerably close together, as in Goniopora ; and the Montipormse, 

 which have a spongy intermediate tissue. Nearly all the species are reef-builders, and all are shallow 

 water dwellers. Porose Corals existed in the Paleo- 

 zoic agi 1 . 



Other great divisions of the Madreporaria are the 

 Tabulata, Tubulosa, and Rugosa. 



It has been noticed, in treating of the Hydrozoa 

 (page 292), that some of the Tabulata belong to that 

 class. There are some of this great group of the 

 Corals which cannot yet be classified satisfactorily. 

 Some certainly belong to the Alcyoiiaria, a group 

 which will be considered in a future page, and one 

 genus, Pocillopora, which has tabular and twelve ten- 

 tacles, with very rudimentary septa, probably should be 

 referred to the Aporose division of the Madreporaria. 

 Others cf the old group Tabulata may be Bryozoa. 



The Tubulosa contain two genera, which are ex- 

 tinct, namely, Aulopora and Pyrgia, but their classi- 

 ticatory position is very undecided, and probably they 

 were Alcyonarians. 



Lastly, the Rugosa, a grand group in the Palaeozoic 

 age, in which they were reef-builders, has some modern 

 representatives in the small Guynia and Duncania of 

 the floors of the Mediterranean and Atlantic Ocean. 



SUB-ORDER ANTIPATHARIA, OR 

 SCLEROBASIC ZOANTHARIA. 



MAPREPORA TLAXTAGIXEA. 



These are mostly slender and branched animals, 



fixed on to substances at considerable depths, and very plant- or bush-like in appearance. The inside 

 of their stem is solid, and is composed of hard concentric layers, with a central space, and may be 

 corneous or calcareous. It is covered with soft tissue, which is continuous with the polypes which 

 form the outer living part. The whole is, as it were, a colony, and there is great symmetry in its 

 size, colour, and arrangement. The polypes resemble small Anemones ; no hard parts are within 

 their derm, and their base rests on and forms the solid stem or axis. They have six to twenty-four 

 simple tentacles. In the genus Cirripathes, the shape of the stem is that of a stick, and it is covered 

 with little sharp spinules ; and in one from the Fijis the stem is very flexuous, and is often spirally 

 curved, the polypes are green, and the tentacles brown, and the surface is ciliated. The genus 

 Antipathes has a black, hard stem, like ebony, and it is more or less echinulate, and ends in small barbules. 

 The species differ in the kind and amount of branching, and whether they are spiny or not. They 

 live on the floor, at moderate depths, of the Atlantic, Pacific, West Indian, and Indian Oceans, 

 and the Mediterranean Sea. Six tentacles are present, and two mesenteries. In the genus 

 Gerardia the hard stem is branched and rough like shagreen, and the soft tissue is dense, and 

 contains silicious spicules ; but they appear to belong to other animals, and are accidental. 

 There are twenty-four tentacles, and as many mesenteries. The species are from the Meditei*- 

 ranean and West Indies. A vitreous or semi-hyaline-looking stem, more or less fan-shaped in 

 its branching, characterises the genus Hyalopathes, of the Indian Ocean. In all these genera 

 the hard stem is the product of the base, or lower part of the outer skin of the soft polype-bearing 

 textures. 



