MADREPORARIA. 191 



Suh-fam. 2. Schizopathinae. Polyps exhibit pseudo-dimorphism ; each 

 with two tentacles (i.e. 6 to each polyp). Schizopathes Brook ; Eathypathes 

 Brook ; Taxipathes Brook ; Cladopathes Brook. 



Fain. 3. Dendrobrachiidae. With branched retractile tentacles. Axial rod 

 without central canal. Anatomy not known, possibly Alcyonarian. Dendro- 

 brachia Brook. 



Sub-order 3. MADREPORARIA.* 



Colonial, rarely solitary, soantharian polyps, which secrete by the ectoderm a 

 continuous and complicated calcareous corallum. 



This old and apparently well-established division of the Zoantharia is still, 

 from a structural point of view, very imperfectly known. The less important 

 features of structure, viz. the arrangement of the hard parts the corallum has 

 been minutely examined, but the soft parts have been neglected, and had it not 

 been for the investigations of the Oxford School, and of v. Koch, we should still 

 know very little more about them than we do of the soft parts of extinct forms. 

 These investigations which will, we may hope, soon lead to the possibility of a 

 satisfactory classification of the sub-order, have established the following im- 

 portant points: (1) the complete disestablishment of the Tabulate division, 

 which, on examination of the soft parts, has been found to comprise forms 

 belonging to Hydromedusae, Ahyonaria, as well as to Madreporaria ; (2) that the 

 corallum is entirely a product of the epithelial ectoderm, and lies wholly outside 

 the animal ; (3) that the structure of the polyps varies in the different groups, 

 though the Hexactinian type seems on the whole to prevail. The most important 

 deviations from that type, so far known, are presented by those forms, in which 

 the directive mesenteries (if indeed they can be called so) present the same 

 arrangement of their muscles as do the other pairs (Lophohelia, Mussa, EupJtyllia, 

 Hetcropsammia), and the number of mesenteries and tentacles is not a multiple 

 of six. 



Acontia appear to be absent ; but peristomial cinclides are said to be present, 

 allowing of the emission of the much convoluted mcsenteric filaments. The 

 colonies are generally dioecious ; and the gonads are borne upon all or certain 

 of the mesenteries. Pores at the apex of the tentacles seem to be absent. 



Asexual reproduction by budding, or by fission, is always present. In Fungia 

 and its allies there is formed from the egg a fixed nurse-stock, which has the 

 property of nipping off its disc-shaped apical portion, and of forming in its 

 place a new disc. The fixed nurse-stock is a typical polyp with theca and septa, 

 and at first it does not terminate in an expanded disc. When the walls of the 

 theca, which are at first vertical, have widened out into a disc, the lower 

 part of it forms a stalk. It is this stalk which is left after the fission, and 

 which produces a new disc. The new disc is not a bud, but is a product of 

 the growth of the structures already existing in the base of its predecessor 

 (Lister, Q. J. M. S., 29). It is not certain whether the Fungia stock increases 

 by budding. 



* Martin Duncan, "A Revision of the Families and Genera of the Sclero- 

 dermic Zoantharia," Journal of the Linnean Society, vol. 18, 1885. H. N. 

 Moseley, "Report on the Corals," Challenger Reports, 7, 1881. G. C. Bourne, 

 "Anatomy of Mussa and Euphyllia," etc., Q. J. M. S., 27, 1887, p. 21. 

 G. H. Fowler, "Anatomy of the Madreporaria," I.-V., Q. J. M. S., vol. 25 

 to vol. 28. V. Koch, " Ub. d. Verhaltniss v. Skelet u. Weichtheile b. d. 

 Madreporen," Morph. Jahrb., 12, 1886. M. M. Ogilvie, "Microscopic and 

 systematic study of Madreporarian types of Corals," Phil. Trans., 187, 1896. 



