British species of the genus Lagena. 17 



2. Entosolenia marginata. PL II. figs. 15, 16. 



Serpula {Lagena) marginata. Walker, p. 3. tab. 1. fig. 7. 

 Vermiculum marginatum, Mont. \).52A. 

 Lagenula marginata, Thorpe. 



Cell nearly orbicular, compressed, transparent or translucent, 

 especially in a young state, having a slight projection at the upper 

 extremity, towards the end of which is the orifice communicating 

 with the internal tube. The cell is surrounded by a thin marginal 

 lamella, which is continued as far as the oral orifice; within this 

 margin, in old shells, is occasionally a thickened opake portion 

 shaped like a horse-shoe, with the concavity and interrupted part 

 directed upwards, the circumscribed central poi'tion being more 

 transparent. The lower extremity of the cell is sometimes fur- 

 nished with a small external mucro. The internal tube, which 

 is somewhat patulous, is rarely straight, except at the upper por- 

 tion, the remainder being usually arcuated, following the curva- 

 ture of one of the lateral parietes of the cell. Fig. 15 represents 

 a section of the cell, with the tube cut across where the curvature 

 commences. 



This is the most common of our English species. At the Fal- 

 mouth habitat it was comparatively abundant, adhering to a spe- 

 cies of Antennularia, along with young forms of Polystomella 

 crispa, Rosalina glohularis and some others. 



The L. marginata of Dr. Fleming is a concamerated shell ; the 

 Rimula marginata of some authors, and belonging to D'Orbigny's 

 genus Biloculina. 



^00 • • • • STcJ 



Swansea, Rossilly, Manorbeer, Portsmouth, Sandwich, Oban, 

 Kyleakin, Mr. Jeffreys. Scarborough ; Lamlash Bay, Ayrshire ; 

 Mr. Bean. " Eeculver," Walker. Boston, March, Falmouth, 

 le Levant. 



marginata, var. lucida, nob. PI. II. fig. 17. 



Cell elongated, somewhat pyriform, compressed, smooth and 



lining, surrounded by a marginal ring, which instead of being 



thin lamina as in the ordinary type, is usually thickened and 



)mcwhat rounded. It is occasionally scarcely visible, especially 



)wards the base, where however it often projects in the shape of 



mucro. This margin, with the upper and central portions of 



"each of the lateral parietes, are generally transparent, whilst the 



remainder of the cell is usually of a clear shining white ; internal 



'tube generally straight. 



I was much disposed to have regarded this as a distinct spe- 

 Inn. &f Mag. N, Hist. Ser. 2. Vol. i. 2 



