54 



ACTINOZOA. MADREPORARIA. 



synapticulce. Similarly uniting two septa, there are plates, 

 which may be horizontal or oblique, straight or curved, 

 these are the dissepiments (figs. 1 1 A, e ; 13d). Lastly we 

 have the tabulce (fig. 13 B, t), which instead of merely 

 passing across the space between two septa, cut across 

 several, in a typical case going right across the visceral 

 chamber horizontally; but frequently they extend only 

 partly across. The tabulae are arranged one above 

 the other, so that the visceral chamber is divided into 

 horizontal compartments. On the outside of the wall of 

 the coral there are in some forms vertical ridges, which 

 may be smooth or spiny, these are known as the costce, and 

 they usually correspond with the septa. 



A simple coral like that just described may become 

 compound either by budding or by fission. Three kinds 

 of budding may be distinguished, (1) the lateral (fig. 12 A), 

 in which the buds are given off from the sides of the 



FIG. 12. A. Dendrophyllia nigrescens, showing lateral budding, Recent, 

 (reduced one-half). B. Cyathophyllum truncatum, showing calicular 

 budding, Wenlock Limestone, (natural size). C. Syringopora, 

 showing basal budding, Carboniferous Limestone, (natural size). 



polyp, (2) the calicular (fig. 12 B), in which they arise 

 from the calyx, (3) the basal (fig. 12 C), in which the 



