l8 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



eingerollte Ende der urspriinglichen Spirale sich aufrollt 

 und nach hinten und unten geschoben wird (fig. 5 und 6, 

 S. 29U. 30)". 



While the oral end of the spire unrolls, the other end 

 changes the direction of its curvature from right to left 

 (figs. 21 to 27). The various changes in position of the 

 peristomal area and the direction of its ciliary band must 

 be due to unequal growth without as well as within the area. 



As the oral band grows and unrolls, the cytoplasm directly 

 beneath it becomes denser and finer in structure (fig. 12, z), 

 and in the stages shown in figs. 23 and 14 the basal fibre 

 and its lateral branches have appeared, giving the usual 

 triangular cross-section of the band. In a little later 

 stage, the axial fibre is seen extending a short distance 

 above the band (fig. 24), but definite connection with the 

 attachment cup for this new axial fibre and for the origi- 

 nal one is not effected until about the time of separation 

 (figs. 27 and 28). 



During all these changes the Licnofhora moves actively 

 about and feeds, at least in live cultures. 



One pair were discovered when they were connected by 

 only a narrow band of the velum, and for a half hour they 

 whirled round and round apparently struggling to free 

 themselves from one another. At last they separated and 

 the one having the primary oral disc swam away, while the 

 other whirled about in one spot for fully an hour before it 

 became sufficiently adjusted to new conditions to swim away. 



The following tabulated comparison between Licno^hora 

 auerhachii and L. niacfarlandi is based on Wallengren's 

 paper (1894), and the results which I have obtained. It 

 shows in a concise form the salient points of difference 

 upon which this new species is based, as well as some others 

 which a renewed study of the European forms will doubt- 

 less show to be generic in character. Chief among the 

 latter may be cited the axial fibre connecting the attachment 

 disc and the oral band. 



