14 General Morphology of the Protozoa 



short anterior flagella, a longer fifth flagellum, and an undulating mem- 

 brane. A typical dinoflagellate (Fig. 1. 7, J) has a transverse flagellum, 

 lying in a spiral groove (the girdle), and an axial (or longitudinal) flagel- 

 lum extending posteriorly from a lateral or postero-lateral origin. 



Axostyles 



The axostyle (Fig. 1. 8) varies from a filament to a thick hyaline 

 rod, usually joined to a blepharoplast and extending posteriorly along 

 the major axis of the body. The axostyle may end in the body or may 

 project externally, sometimes tapering to a filament which may serve for 

 attachment to the host (124). The anterior end is often expanded into a 



Fig. 1, 8. Axostyles. A. Capitulum and anterior portion of axostyle in 

 Hyperdevescovina insignita; xl800 (after Kirby). B. Slender axostyle in 

 Monocercomonoides pilleata; x3600 (after Kirby and Honigberg). C. Mul- 

 tiple axostyles of Snyderella tabogae; diagrammatic; x350 (after Kirby). 

 D. Tritrichomonas augusta, axostyle with inclusions; xl950 (after Kofoid 

 and Swezy). E. Axostyle with capitulum in BuUanympha silvestri; x750 

 (after Kirby). Key: a, axostyle; b, blepharoplast; c, capitulum; ct, cortex; 

 m, mastigont; n, nucleus; t, trailing flagellum; u, undulating membrane. 



