MEMBRANIPORA LINE ATA. 145 



Habitat. Onweedj stone^ shelly &c., from between tide- 

 marks to deep water. It is more especially a littoral 

 form^ and is developed in extraordinary luxuriance on 

 some of the Fuel. 



Localities. Common, and widely distributed. Shet- 

 land, on Fiici and Lammarice ; Hebrides (A. M. N.) : 

 Wick (C. W. P.) : Northumberland and Durham, from 

 tide-marks to deep water, frequent on Patella lavis 

 (Alder) : Isle of Man ; Ilf racombe, on Laminaria ; South 

 Devon, between tide-marks ; Mount's Bay, under stones 

 (T. H.) : Hastings, normal and var. a (Miss Jelly) : &c. 



Geographical Distribution. Roscoff, on Laminaria 

 saccharina, common (Joliet) : coasts of Skandinavia, in 

 shallow water, common (Smitt): Baltic (Lenz): Spitzbergen 

 (Loven): Davis Strait, 100 fms. ; Reykjavik Harbour, Ice- 

 land, 15-20 fms. (Wallich) : Nova Zembla, 3-50 fms. ; 

 Kara Sea (Nordenskiold, fide Smitt) : South Labrador 

 (Packard) : Adriatic (Heller) : Florida, on coral, 42 fms. 

 (Pourtales) : New Zealand (F. W. Hutton) . 



Range in Time. Italian Pliocene and Miocene deposits 

 (Manzoni) . 



M. lineata is readily distinguishable from the allied 

 British species, and on the whole is very constant in 

 character. Smitt unites it with M. craticula, M. unicornis, 

 and several others under one specific designation. But 

 there are no intermediate varieties, so far as I know, con- 

 necting together the present species and M. craticula : 

 they are well-defined forms, each with a marked fades, 

 separated from one another by a group of constant charac- 

 ters, and exhibiting, according to my experience, a very mo- 

 derate amount of variability. It may be remarked, too, that 

 amongst Smitt's figures referred to his M. lineata there is 

 certainly nothing that makes any approach to M. craticula. 



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