MEMBRANIPOEA CATENULAEIA. 135 



area, occupying the whole of the upper part of the cell, 

 ohlique, oval, slightly expanded below and contracted 

 above, with a plain, rather wide and flat border. Ooecia 

 none. 



Habitat, On shells, stones, Algae (rarely), &c. from deep 

 water. 



Localities. Generally distrilmted. Phince, off the 

 Deadman and west to the Lizard (Coucli) : South Devon, 

 very common (T. H.) : Isle of Wight (W. T,) : St, 

 Andrews, less common than Hippothoa divaricata (Dr. 

 M'Intosh) : Pinnae, I. of Coll (Landsb.) : Shetland, on 

 stones, 40-170 fathoms; The Minch (A, M. N,) : Pinna, 

 coast of Cork ; co. G-alway, on Buccinnni Zetlandicum; 

 off the Gobbins, co. Antrim, 40 fathoms (W. T.) : off 

 Mull of Cantire, 40 fathoms (Hyndman) : &c., &c. 



Geographical Distribution, On mussels, Algse, &c. 

 Adriatic (Heller) : Naples (A, W, Waters) : He de Re, 

 France (D'Orbigny) : North Sea, " extra Norvegiam," on 

 Gorgonia, 200-300 fathoms (Baron Uggla) : Gulf of St, 

 Lawrence (Dawson) : Labrador (Packard) : ? Grand Mauan 

 (Stimpson), 



Range in Time, Palaeolithic; Red Crag (part.); Cor. 

 Crag (A. Bell) : Scotch Glacial deposits (Geikie) : Post- 

 pliocene deposits, Canada (Dawson) : Italian Pliocene, 

 Calabria (Manzoni) : Pliocene of Bruccoli, Sicily (A. W. 

 Waters) . 



M. catenularia has been ranked by most authors in the 

 genus Hippothoa ; but its large aperture, occupying a great 

 proportion of the front of the cell and closed in by a 

 membranous covering, at the top of which the oral valve 

 is placed, is a character which separates it from the other 



