TEINEMA LINEARE. 93 



sub-circular; aperture circular, oblique, invaginated; 

 plasma colourless, granular, partly filling the test ; 

 nucleus containing a single nucleole, placed posteriorly ; 

 two contractile vesicles usually present ; pseudopodia 

 long, attenuate, radiating, usually one to three in 

 number. 



Length 18-35 /A; breadth 7-1 7 /x; aperture 3-6 /A; 

 scales 3-6 jot in diameter. 



Habitat. Mosses, sphagnum, and aquatic vegetation. 

 Generally distributed. 



This small species is even more common than the 

 preceding ; scarcely a tuft of moss can be found which 

 does not contain numerous individuals. 



FIG. 153. Outlines of tests of Trinema lineare showing angle of 

 aperture varying from normal (a) to terminal (/), and abnormal 

 evaginated aperture (g). x 650. 



The curvature of the small scales forming the test 

 is generally such as to present a continuous outline, 

 but they may be convex, flat, or, rarely, slightly 

 concave. The angle at which the aperture is placed 

 varies more frequently in this species than in T. 

 enclielys ; while 30 is the normal angle between the 

 plane of the aperture and the longitudinal axis of the 

 test, every variety of inclination between this and 

 90, or a terminal aperture, may occur. Abnormal 

 evaginated apertures are also occasionally found. 



In structure the test is similar to that of T. encheli/s, 

 but owing to its small size and extreme transparency 

 the details can seldom be distinguished without special 

 preparation and the use of a high magnification. 



Conjugating individuals are not uncommon. From 

 T. enchelys, the only species with which it is likely to 



