British species of the genus Lagena. 19 



Cell ovato-globose, with a slight projection superiorly, at 

 the extremity of which is the small circular oral ? orifice. Sur- 

 face beautifully ornamented with numerous, small, white, concave, 

 irregular, areolar spaces, separated by elevated, transparent, reti- 

 cular lines of demarcation. These areolse are irregular in form 

 and distribution, being sometimes nearly round or oval, but more 

 usually exhibiting a marked tendency to become hexagonal, the 

 lower ones being usually the most elongated. Occasionally the 

 areola3 are transparent and the reticulations milky. In this state 

 it appears to be the L. reticulata of MacGillivray : one part of his 

 description alone does not agree with my specimens ; he speaks 

 of its being " considerably compressed.^^ This however may have 

 been an accidental circumstance, as all the species, both of En- 

 tosolenia and Lagena, are liable to a considerable degree of de- 

 formity. Internal tube patulous, usually shorter than in E, 

 globosa, and generally with a small dilatation or spherical cavity 

 a little below the oral ? orifice. The base of the cell is sometimes, 

 though rarely, furnished with a small umbo. 



In the figure of this exceedingly variable species, given in the 

 Supplement to Montagues ' Testacea Britannica,^ the areolse are 

 made to represent scales overlapping each other. This appear- 

 ance, though not natural, is easily obtained, by viewing the object 

 obliquely and by throwing the microscope a little out of focus, 

 and I have no doubt would be the aspect presented by the object 

 when viewed under the imperfect instruments used in the time 

 of Mr. Walker. Dr. Fleming considers these areolse to be " pa- 

 rietal cells. ^^ They are however merely concavities in the exterior 

 of the cell. They are usually to be traced in the form of opake 

 spots in the decalcified membrane. 



I possess one curious abnormal double specimen of this species, 

 like that of E. globosa already described. There are two cells, 

 united inferiorly, and having each one central oral ? orifice at the 

 opposite extremity. 



Long. Diam. 



1 1 



To (T • • • • T77 



1 1 



TT7 • • • • TJ(J 



T^TT • • • • y-gi? 

 " Seasalter, Mr. Boys," Montagu. Torbay, Swansea, Mr. Jef- 

 freys. Lamlash Bay, Ayrshire, Scarborough, Mr. Bean. " Bay 

 of Aberdeen," Prof. MacGillivray. Boston ; March : rare. 



Entosolenia squamosa, var. a. catenulata. PI. II. fig. 20, 

 Lagenula catenulata, Jeffreys MSS. 



Cell ovato-globose, usually hyaline and transparent; areolse 

 very small and numerous, square or hexagonal, arranged in per- 

 pendicular rows, having parallel horizontal divisions, which are 



3* 



