303 



CHAPTER XIX. 

 ZOA NTHARI A— continued. 



MADREPORARIA FUNGIDA AND PERFORATA. 

 SECTION III. MADREPORARIA FUNGIDA. 



This section includes simple or composite Madreporarians, in which 

 the interseptal loculi are crossed by trellis-like calcareous bars (" syn- 

 apticula "). In the composite forms, where adjacent corallites are 

 connected by prolongations of their septa (" septo-costae "), the inter- 

 spaces between these prolongations are also synapticulate. The 

 septa are lamellar, and are usually solid, though occasionally per- 

 forations exist. When there is a basal plate it is usually perforated 

 by apertures, but it may be imperforate. Endothecal structures 

 (dissepiments and columella) may or may not be developed. Ten- 

 tacles in the living forms " short, lobe-like, scattered, sometimes 

 obsolete" (Duncan). 



So far as certainly known, the section of the Madreporaria Fun- 

 gida has no Palaeozoic representatives ; but the Secondary and Ter- 

 tiary deposits have yielded a large number of fossil forms, only a 

 few of the more important of which can be alluded to here. 



By Professor Martin Duncan the section of the Fungida is di- 

 vided into the following five families : — 



Family i. Plesiofungidce. — This family is related to the Aporosa, 

 and comprises simple or composite Fungida, in which dissepiments 

 exist in addition to the synapticula, and the septa are usually solid 

 and imperforate. The principal genus in this family is T/iamnas- 

 trcea, including a large number of species, which range from the 

 Trias to the Miocene Tertiary, and have a very wide geographical 

 distribution. In this genus the corallum is composite and is usu- 

 ally massive or lobate in form, sometimes laminar or encrusting ; 

 while the corallites have ill-defined walls. The calices (fig. 184, a) 

 have distinct centres, but are shallow, and the septa become con- 



