238 CILIATE FIBRILLAR SYSTEMS 



the basal granules with perfectly regular transverse commhsures. In the 

 region posterior to the frontal lobe, the commissural fbrils branch, form- 

 ing numerous collaterals extending in various directions. These unite 

 with transverse and longitudinal fibrils. 



The pellicular thickenings of the frontal lobe are present in the form 

 of heavy, deeply staining fibers which alternate with the ciliary rows. Be- 

 tween the anterior ends of these and the anterior ends of the dorsal 

 rows of cilia is a delicate fretwork, or polygonal area. The boundaries of 

 polygons correspond with the boundaries of a double row of large 

 vacuoles. Posterior to the frontal lobe, the heavy fibrils become fine and 

 lie so close to the neurofibrils that they are almost indistinguishable from 

 them. Similar fibrils are evident on the dorsal surface of the organism 

 only at the anterior end (Fig. 85). 



Methods 



Fixatives: Schaudinn's, Da Fane's, 2-percent osmic acid, Flemming's with- 

 out acetic acid (the two latter for sections) . 

 Stains: Iron-haematoxylin, Yabroff's silver method. 



Eupoterion pernix (MacLennan and Connell, 1931). — Most of the 

 longitudinal ciliary fibrils of the body take their origin from a heavy bar, 

 the anterior connective fibril, that lies dorsoventrally across the anterior 

 tip, whence they extend to the posterior end, where they fuse. Additional 

 fibrils arise in pairs along the pre-oral suture line and these fuse mostly 

 also at the posterior end. Each basal granule gives off one or two com- 

 missural fibrils to adjacent ciliary rows, resulting in a fairly regular lat- 

 ticework (Fig. 86). 



The neuromotorium lies beneath the wall of the cytostome. The fibrils 

 of the four pairs of oral ciliary rows along the oral groove are fused in 

 a V-shaped figure at the apex of the suture line. All of these end directly 

 in the motorium or are closely connected to it by the transverse fibril or by 

 the longitudinal ciliary fibrils. The transverse fibral lies across the end 

 of the neuromotorium; its right end joins the pharyngeal fibrils, thus 

 forming a pharyngeal strand; and its left end fuses with the two outer- 

 most peristomal ciliary fibrils and ends farther left in a connective fibril 

 of adjacent outer rows of cilia. The two rows of cilia arising from the 

 anterior ends of the outer peristomial rows (of the ordinary peripheral 



