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the Carboniferous. Of seventeen genera that date from the 

 Devonian period, eleven are special to it, and five pass into the 

 Carboniferous period, which has seven genera special to it. The 

 Permian has only one proper to it, the Polyccelia. 



6th Sub-Order. — Zoantharia tubulosa are characterised by 

 negative rather than by positive characters. They have neither 

 septa, columella, nor tabulae in the visceral chamber, and we 

 distinguish only some feeble striae on the walls, which are 

 imperforate. They form one family, the Atjlopoeid^, special to 

 the Palaeozoic epoch. 



6th Sub-Order. — Zoanthabia cauliculata are composed of 

 Polypes, supported on a sclerobasic corallum, similar to those 

 of Isis and Gorgonia. The surface of the Polypary is smooth 

 or spinous, but wants the longitudinal striae observed on the 

 sclerobasis of the genera belonging to the order Alcyonaria. 

 This small group is represented by the family Antipathid^. 



The Alcyonian Polypi are provided with bi-pinnate tentacula, 

 and only eight perigastric membranaceous laminae, containing 

 the reproductive organs. Their dermal tissue is consoHdated by 

 isolated spiculae or nodular concretions, and the Polypary has a 

 stem-Hke arborescent character. As the visceral chamber is not 

 sub-divided by longitudinal septa, the chalice never presents any 

 appearance of radii. The corallum is in general composed of 

 epidermic tissue, and forms a ramose stem or axis in the centre 

 of the compound mass formed by the gemmation of the Polypi. 

 The sclerobasis (or foot secretion) is always covered by a soft 

 dermic tissue, and increases by the addition of concentric layers. 

 This order includes four families, Alotonid^, Gokgonid^, 

 PENNATULiDiE, and Graptolithid^. 



The AtcYONiDiE have a dermic tissue, consoHdated by 

 spiculae, but no trace of a central stem. In one of the groups — 

 TuBipOEA — the Polypi are enclosed in tubular pipes, associated 

 or connected together by super-imposed horizontal floors. 



