HOUNERID^. 467 



Family III. — Horneridae. 



HoRNERiD.E, Smitt, Kritisk Fort. 1866. 

 CRtsiNiD.E (part.), D'Oi'bigny. 

 Les TunuLiroKiENs (part.), Milne-Edwards. 

 Tdmoneid.e (part.), Busk, Crag Pol., and B.M. Cat. 

 Idmonead.e (part.), id. Engl. Cyclopaedia. 



ZocECiA opening on one side only of a ramose zoarium, never 

 adnate and repent. 



Genus HORNERA, Lamouroux. 



Der. Named aft«r M. Horner, astronomer to the expedition round the 

 world under Krusenstern. 



MiLLEPORA (part.), Linn. : Pallas: Solander: &c. 



HoRNERA, Lamx.(lS21): Milne-Edwards (part): D'Orbigny: Smitt: Busk: 



&c. 

 Retepora (part.), Lamk. : Goldfuss. 

 SiritoDiCTYUM, Lonsdale. 



Generic Character. — Zoarium ei^ect, ramose, some- 

 times reticulate. Zocecia tubular, opening on one side only 

 of the branches, disposed in longitudinal series, the cellife- 

 rous surface often traversed by wavy anastomosing ridges. 

 OcEciuM a distinct chamber {not a mere irregular inflation 

 of the surface of the zoarium), placed dorsally or in front. 



The genus Hornera is connected with the Tubuliporidoe 

 through Idmonea, to which it bears in many points a very- 

 close resemblance. It embraces two very characteristic 

 groups : in one the zooecia are covered in front by a cal- 

 careous crust, which takes the form of wavy longitudinal 

 ridges, often anastomosing, whicli wind round and inclose 

 the orifices of the cells, and give a fibrous appearance to 

 the surface of the zoarium. Of this section, which may 



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