106 University of California Publications in Zoology [VOL. 13 



ordentlich verzweigten Fibrillensystem, " but which represents only a 

 part of the complicated "Fibrillenapparates" and is to be regarded 

 as a particular structure in the entoplasma. These "Fibrillen" are 

 longitudinal and are internal to the transverse "Fibrillen" next 

 described. 



2. The whole body is surrounded by a large number of almost 

 parallel transverse "Fibrillen" which take their origin from one edge 

 of the ' ' Stiitzapparat " (his fig. 36, qu. fibr.) and pass around the 

 dorsal side of the body to their attachment in the opposite edge of the 

 "Stiitzapparat." They assume considerable size when they have a 

 particular function to perform. To quote (p. 158), "So finden wir 

 oberhalb, der Membranellenzone zwei quer Fibrillenbiindel (Fig. 36a, 

 &), die in einem bestimmten Abstand, durch mehr oder weniger regel- 

 maBig angeordnete Langsfibrillen verbunden, stehen. ' ' 



Although the same fixing and staining methods (viz., Schaudinn's 

 alcoholic sublimate solution followed by Heidenhain's iron-alum 

 haematoxylin) that Braune used for 0. purkynjei have been used on 

 D. ecaudatum it was not possible to demonstrate, in this organism, 

 either the "Filbrillenschicht" or the transverse "Fibrillen." Ah ex- 

 amination of the microphotographs (pis. 6, 7, figs. 11-33) will show 

 that although in many of these sections in which, even in the prints, 

 the separate granules of the macronucleus (pi. 7, figs. 27-29), the 

 separate cilia in the membranelles (pi. 6, figs. 14, 15, 19 ; pi. 7, fig. 

 25), and the individual bacteria within the food vacuoles (pi. 7, fig. 

 33) may be fairly well made out (and certain it is that all details may 

 be seen to much better advantage in the original sections) there is no 

 evidence of the presence of these above described "Fibrillen." The 

 fine parallel lines of the lower ends of figures 12-14, plate 6, might at 

 the first glance be confused with the " Fibrillenschicht " of Braune, 

 but on a closer study it will be noted that these lines are surface mark- 

 ings (cf. fig. 11). Also an examination of figures 26 to 32 will show 

 that in the case of D. ecaudatum the layer separating the internal 

 entoplasm from the more external layers (ectoplasm and cuticle) is a 

 continuous, homogeneous membrane rather than a layer of "Fibril- 

 len," as pictured and described by Braune for 0. purkynjei, with the 

 possible exception, as noted in the main body of my paper, of the 

 extreme posterior end of the body in which the oesophageal wall lies 

 so close to the boundary layer as to defy a microscopic separation and 

 identification of the two layers. 



3. In his description of the lips of the dorsal membranelle zone 

 (p. 157), he says, "In den Wanden aiiBern Saumes trifft man regel- 



