ANTHOZOA. 23 



Interesting from a like high antiquity are the impressions 

 on the Cambrian slates of Wicklow, resembling specimens of 

 the Sertularia argentea, and which are referred to the polype- 

 genus Oldhamia. One species (fig. 3, 2) presents an axis with 

 radiating groups of branches diverging alternately at regular 

 intervals from either side. The original flexibility of the 

 compound organism is shewn by the confused and compressed 

 state in which the whole mass is sometimes found, and from 

 the more or less folded state of the little fans. Oldhamia 

 may be "bryozoal," but, if the interpretation of the parts 

 springing from the axils, as " oviferous capsules," be correct,* 

 the genus is " hydrozoal." 



Class II.— ANTHOZOA. 



In this class of Polypes the tentacles are hollow, and, in 

 most, with pectinated margins. The polypary is usually in- 

 ternal, and forms the bodies more properly called " corals " 

 and "madrepores." 



Great doubt attaches to some of the fossils referred to this 

 class of Polypi. The terms "Oorgonia" and "Alcyonium" 

 have been applied to objects not well understood, and usually 

 proving to be Bryozoa and sponges. The Lower Silurian 

 fossil called Pyritonema consists of a fasciculus of silicious 

 fibres, and has been supposed to be related to the glass 

 zoophyte (Hyalonema). The miocene deposits of Piedmont 

 contain a species of the Mediterranean genus Corallium, an 

 Antvpathes, and an Isis (or Isisina, d'Orb.), which is also 

 found in Malta. The London clay contains one coral (Gra- 

 phtdaria), referred to the Pennatulidaz, and two Gorgonidce 

 (Mopsea and Websteria). This is the earliest authentic evi- 

 dence of the family of existing Anthozoa characterised by a 



* Kinahan, Trans, of the R. Irish Acad., xxxiii. p. 547. 



