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BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



Fig. 22. — Genus Spiralaria Busk, 1861 



A-I. Spiralaria denticulata Busk, 1861. A. Ordinary specimen, natural size. 

 B. 1, portion of Figure A showing two blunt processes on each side of the mouth; 

 2, portion showing a series of large frontal processes along the margins of the 

 cells; 3, cell from near the end of the same specimen showing the minute sub- 

 marginal denticles; 4, portion of Figure A; 5, cell towards edge of same showing 

 the submarginal denticles (after MacGillivray, 1879). C. Preparation by 

 transparency showing anatomical structure. D. An avicularium and its mandi- 

 ble. (C, D, after Busk, 1885.) E. An ovicelled zooecium. The ovicell is 

 enclosed in an avicularium, X40. F. A transverse section through a branch; 

 cr, cryptocyst; X55. G. A sagittal section through an avicularian mandible 

 to show the internal cavity which corresponds with the vestibular cavity in the 

 operculum. H. A portion of the basal surface to show its composition of celllike 

 small plates (cell mosaic). (E-H, after Levinsen, 1909.) I. Lateral wall 

 showing septulae and the internal denticles, X25. 



J, K. Spiralaria spinuligera Hincks, 1882, lateral and distal wall, X25. 



L, M. Spiralaria dentigera Hincks, 1882, lateral and distal wall, X25. (I-M, 

 after Waters, 1896.) 



