20 Mr. W. C. Williamson on the genus Lagena. 



sometimes straight and at others arcuated. This form is merely 

 the E. squamosa with the areola? in perpendicular rows instead of 

 being irregularly distributed over the surface. Sometimes these 

 areolae exhibit a tendency to assume the ordinary white opake 

 appearance of the common form. I have seen specimens in which 

 one side exhibited the arrangement in fig. 19, and the opposite 

 one that of fig. 20 ; thus showing the identity of the two forms. * 



Lon S- -xhn > diam - lU- 



Swansea, Sandwich, Mr. Jeffreys. Boston : very rare. 



Entosolenia squamosa, var. (3. scalar if or mis, nob. PI. II. figs. 



21, 22. 



Closely resembling the last in the distribution of its areolae, 

 only they are very large and few in number ; usually square or 

 hexagonal, the horizontal lines of division being most frequently 

 a little arcuated. The texture of this variety is highly hyaline, 

 and commonly occurs amongst the young states of E. squamosa. 

 As in the preceding example, I have seen specimens in which 

 one side exhibited the arrangement of the areola?, characterising 

 the present form, whilst the opposite one presented that of the 

 succeeding variety. 



Long. Diam. 



1 1 



lHo ' ' * * TT¥ 



1 _ l _ 



135 • * ' ' 2Uo 



Kyleakin, Mr. Jeffreys. Lamlash Bay, Ayrshire, Mr. Bean. 

 Boston ; March : very rare. 



E. squamosa, var. 7. hcxagona. PL II. fig. 23. 



Areola? large, hexagonal, concave, not arranged in well-marked 

 perpendicular rows. The cell is often more conical, opake, and of 

 a browner aspect than in the other forms, but numerous interme- 

 diate specimens link them all together, both as regards the colour, 

 form and arrangement of the areola?. 



Lon S- TFT 5 diam - »ho- 



Oban, Kyleakin, Mr. Jeffreys. Lamlash Bay, Scarborough, 

 Mr. Bean. Boston ; March : very rare. 



The Vermiculum lacteum of Montagu is not a Lagena, but the 

 Arethusa lactea of Fleming, a species of Polymorphina of D'Or- 

 bigny. Vermiculum retortum, Mont., is a very young state of one 

 of D'Orbigny's family of Agathistegues, probably the Vermiculum 

 bicorne, Mont. Vermiculum urna of Montagu, as I have already 

 stated, I believe to be the same as my Entosolenia lineata. Mr. 

 Jeffreys suspects it to have been the ovary of a coralline. The 

 Lagenula marginata of Fleming belongs to D'Orbigny's genus 

 Biloculina. 



Manchester, June 25, 1847. 



