454 



site. On shells it is commonly wholly adnate, and takes 

 on many diverse shapes ; but in the very beautiful variety 

 radiata it adheres by a central disk only, around which 

 the lobes or branches rise with much regularity. When 

 attached to the stems of zoophytes it is almost entirely 

 free and erect, and forms the prettiest coral-like growths. 

 In its young state it assumes when repent a simple clavate 

 figure, the zoarium, which is much attenuated towards the 

 point of origin, expanding gradually towards the apex, 

 and having the cells arranged in series on each side of the 

 central line. In this condition it is the Obelia tubulifera 

 of Lamouroux (Plate LX. fig. 2). 



The delicate purplish colour and the bright vitreous 

 surface are characteristic points. The branches teraiinate 

 above in thick cellular extremities. 



HABITAT. On old shells, zoophytes (especially Hydrall- 

 mania falcata) , and Algse, from the littoral region to very 

 deep water. 



LOCALITIES. Generally distributed. Var. a, on Cornish 

 Pinna (T. H.). 



GEOGRAPHICAL DISTRIBUTION. France, S.W. (Fischer) : 

 Roscoff, on Algae, common (Joliet) : Mediterranean 

 (Lamx., Heller) : Naples, 2 fathoms and 20-30 fathoms 

 (A. "W. Waters) : Scandinavian coasts, Bahusia to Fin- 

 mark, from the littoral region to very great depths (Smitt) . 



RANGE IN TIME. Scotch Glacial deposits (Geikie) : Plio- 

 cene, Castrocaro (Manzoni) : Sicilian Pliocene (Waters). 



