1 1 6 Introduction to Animal Morphology. 



only living genus ; these are referred by some to Hydrozoa. 

 3. Thecidae Palaeozoic ; thick, massive ; tabula? many ; septa 

 not reaching- the centre, but uniting peripherally into a dense 

 spurious coenenchyma. 



Sub-order 3. Tubulosa Palaeozoic corals with a simple 

 pyriform (Pyrgia) or connected (Aulopora) colony with no 

 columclla nor tabula. 1 , and stria.' representing septa, and with 

 an imperforate theca. In Aulopora the ca-nenchyma is basal. 



Sub-order 4. Perforata corals with a porous or netted 

 ( d-neiK hvma, with no tabula;, well-developed septa, and 

 rudimental dissepiments ; theca; not costate. This includes 

 the families : i. Madreporidai- compound with thick, simply 

 porous thecie, not distinct from the ca-nenchyma ; chief radii 

 little or not at all perforated : two strong septa mav reach the 

 middle Madrepora . or a spongiose columella may exist with 

 clo-elv converging lamina,' (Eupsammidae). Turbinarinaj 

 have six strong M-jita developeil without (Astraeopora), or with 

 Turbinaria). 2. Poritida- have no lamellar septa, 

 !)iit trab- bacilli form a in-tied skeleton ; the- ca!\ 



may have rudimental dissepiments; cienenchyma either 

 netted, spongy, >eparate (Alveopora), or indistinguishable' 

 from the cah .mmocora\ or else rudimental or none 



(Poritinae). 



Sub-order 5. Aporosa with an imperforate (except in 

 family 7), compact, lamellar sclerenchyma ; strong, ran-lv 

 perforate' septa: well developed, often costate the- 

 chambers open for their whole extent, or partly closed bv 

 dissepiments <ir synapticulaj ; thecae and septa better de 

 loped than in other corals. This includes eight famil 

 i. Turbinolida; simple: multiplying by fission or budding ; 

 no ctenenchyma, dissepiments, nor synapticulcc (except in 

 (\eiioi\athus); surface granular. A columella may or mav 

 not exist, and when present it may be surrounded bv one 

 Caryophyllinae), or many (Trochocyathinae), or no ( irclets of 

 bacilli. 2. Dasmiidx Eocene corals with each se|)tum made 

 up of three lamella attached to the costate thecae. 3. Stvlo- 

 phorida) have abundant loose spinose coenenchyma ; septa 

 large, and costae strong; central cavity interrupted, not filled 

 by dissepiments ; gemmation irregularly lateral. 4. Oculi- 



