Introduction to Animal JMorpliology . 1 15 



Thalassianthince — tentacles all compound, outer hooked, 

 papillose (Heterodactyla), or the inner with rounded warts 

 (Sarcophianthus). The stem of the branched tentacles may 

 be warty (Ph3-manthus), or filamented ( Actineria) ; the branches 

 may be pear-shaped (Actinodendron), or feathery (Thalas- 

 sianthe). 



Order 2. Sclerodermata (Madreporaria) — colonies, 

 rarely simple ; skeleton enderonic, continuous, cal- 

 careous, with hexameral symmetry (tetrameral in 

 Rugosa). This includes the reef-building corals of 

 past and present ages. 



The following sub-orders are included: — i. Rugosa (sur- 

 mised to belong to Hydrozoaallied to ^lilleporidae), Palaeozoic'^" 

 with thecae, complete tabula? and rudimental, or perfect im- 

 perforate septa, without synapticulse ; in multiples of four. 

 They have no true ccenenchyma, and increase by parietal or 

 calycular budding, not by fission. Four families are con- 

 tained : — I. Stauridae — simple or branched, with incomplete 

 septa, united by lamellar dissepiments, the four primary septa 

 forming a cross. 2. Cyathaxonidae — simple, with complete 

 septa and one septal groove ; dissepiments and tabulae none. 

 3. Cystiphyllidse — simple, vesicular, with slight septa, and 

 bladder-like endotheca ; sometimes an operculum to the 

 calyx. 4. Cyathophyllidae — simple or branched, with incom- 

 plete septa and tabulae ; endothecae closing the chambers ; 

 columella present (Axophyllinae), or none ; septa regular 

 (Cyathophyllinae), or irregular (Zaphrentinse). The Devonian 

 Calceola has an Operculum of one, Goniophyllum of four 

 valves. 



Sub-order 2. Tabulata — hexameral corals with tabulae and 

 few imperfect septa, including the families : — r. Seriato- 

 poridse — tree-like ; ccenenchyma abundant, compact ; septa 

 weak or bacillar ; tabulae few ; chambers filled by the thick 

 wall and columella ; palaeozoic, except the Red Sea Seriato- 

 pora. 2. Favositidae — tabulae strong; thecae united to their 

 neighbours, with little or no coenenchyma ; Poecilopora is the 



* Except the Cretaceous and Eocene Stauridian genus Holocystis. 



i2 



