1919] 



Kofoid-Swczij: TrichoiiympJia campanula 



to the iuner border of the alveoli. The outer zone between the alveoli 

 and the surface ridges has here almost disappeared, the alveoli abut- 

 ting on the bases of the ridges, from which they are rather widely 

 separated anteriorly (pi. 5, fig. 4). 



A distinct alveolar zone h'ing in the ectoplasm is a ciliate rather 

 than a flagellate characteristic. It is not, however, entirelv unknown 



Fig. C. Trichonymplia camininida. Sketches of the anterior end of the body 

 to show its great mobility. Figure 2 illustrates the successive movements used in 

 moving forward through the thick intestinal contents. X 200. 



in the latter group. In the subgenus PachycUniuin of tlie genus 

 Gynmod'inimn, among the dinoflagellates, the difl'erent species are 

 provided with a difl:erentiated ectoplasm the outer layer of which 

 consists of rather large alveoli (Kofoid and Swezy, 1919rf). 



Transverse Myonemes: The innermost layer of ectoplasm, be- 

 neath the alveolar and oblique fiber zone, is occupied by the transverse 

 myonemes (fig. B, tr. my.). These difi'er in structure from the oblique 



