SOME ROTIFERA FROM SPITSBERGEN. 325 



Macrotrachela papillosa Thompson, 

 I think only one example of this variable species was found, 

 and in the " dry tundra " (Z 25), This form was also seen 

 in the 1896 collections, 



Macrotrachela plicata hirundinella (Murray). 

 Some dead specimens could be recognised as belonging to this 

 variety. The distinctive processes were only of medium length. 

 The type form was seen in the 1896 collections, but was not 

 detected in the present series. Both the type form and this 

 variety were seen by Murray (5). 



Macrotrachela quadricornifera Milne. 

 A few specimens of this cosmopolitan species also occurred in 

 the " dry tundra " (L 25). 



Rotifer sordidus {Western). 

 The specimens seen of this variable species seemed to be all 

 typical. They came from the ground moss from Cap Boheman 

 and from the " dry tundra " from Klaas Billen Bay. 



Rotifer tardigradus Ehrenberg. 

 The few specimens seen were all of the ordinary type, and call 

 for no comment. 



Pleuretra alpium Ehrenberg. 



This species is noteworthy as the only rotifer recognised by 

 Ehrenberg when in 1869 he examined some mosses which had 

 been collected in Spitsbergen in 1867. 



It occurred in the mosses which I examined in 1897. On the 

 present occasion no single one of the few specimens seen showed 

 any sign of life. Also seen by Murray (5). 



Pleuretra Brycei (Weber), var. (fig, 4). 

 I found in the mosses from the gatherings L 19 and L 21 a 

 practically spineless form which I have thought it worth while 

 to figure in its customary feeding position, as no really satis- 

 factory figure of this usually spinous and exceedingly variable 

 species has yet been published. The type form has a transverse 

 row of spines arising from the longitudinal skinfolds of the back, 

 where these reach the rear of the third segment of the central 

 body. At this point the skinfolds, which are rather stiff and 



