DIASTOPORA PATINA. 101 



all proportion to the function assigned them ; but it 

 would be difficult to suggest a better interpretation, and 

 it will do good service by giving direction to inquiry. 



In an early stage of growth the zoarium bears much 

 general resemblance to a young Tubulipora, consisting of 

 a short stem, which originates in the usual circular disk, 

 and a semicircular or somewhat flabellate lobe or expan- 

 sion, covered with zorecia, and with a very broad laminar 

 edging (Plate LXV1. fig. 2) . Further development results 

 in the extension of the lamina and celliferous crust around 

 the primary germ, so as to form a circular discoid figure, 

 of which it becomes the centre. 



HABITAT. On shells, stones, Algae, coral, &c., from 

 almost all depths. 



LOCALITIES. Very common. Cornwall, deep water 

 (Couch) : South Devon, abundant; Torbay (proliferous 

 form) (T. H.) : Northumberland (Alder) : St. Andrews, 

 deep water, especially on Mytilus modiolus (Dr. M'Intosh) : 

 Hebrides (A. M. -N.) : Shetland, to 170 fathoms, proli- 

 ferous form frequent (Barlee, Norman) : Strangford 

 Lough (W. T.) : &c. 



GEOGRAPHICAL DISTRIBUTION. Roscoff (Joliet) : France, 

 S.W. (Fischer) : Adriatic (Heller) : North and Arctic seas, 

 5-10 fms., on Algae, Flustra, &c., on shells and coral, 

 50-100 fms. (Smitt) : Bahusia (Loven) : South Nor- 

 way (Lilljeborg) : Finmark (Sars) : South Labrador 



(Packard). 



Fig. 24. 



O.iviuiii ..I It. K 



