"^'OL. 3] Bovarcl. — Condylo stoma patens. 349 



wulst" by Maier (:03), {Bl. PI. 4, fig. 10 b). It is three cor- 

 nered, the lower corner terminating in a fiber which connects 

 together the "Basalwiilsten" as shown in PL 34, fig. 5 (Maier, 

 Ef. PI. 4, fig. 10 b). This end fiber is supposed to be contractile, 

 but not in any way connected with the myonemes of the body. 

 Others have supposed that this end fiber must have some nervous 

 function such as coordination of movement because it connected 

 the "Basalwulsten" one to the other (Maier :03, PI. 4, fig. 10 c). 



The membranellae are regarded as a fusion of many rows of 

 cilia. The fact that the buccal cavity is entirely without cilia has 

 led to the suggestion that the cilia have migrated from this area 

 to the edge and here become cemented together, forming a series 

 of broad fan-like organs. 



Undulating Membrane. — This is a broad thin transparent 

 membrane which lies in the buccal groove and is attached at the 

 base of the right oral lip. The breadth of the membrane is such 

 that it will reach clear across the peristome field when the left lip 

 is not extended so that the buccal groove becomes a funnel wath 

 the small end leading into the mouth. 



In living animals the membrane appears as a more or less 

 homogenous structure traversed at intervals by fibers. In sec- 

 tions the membrane appears to be made up of many fibers, each 

 ending in a large basal body located in the ectoplasm (PL 34, 

 fig. 7-S). These fibers run the full width of the membrane and 

 are very close together. ]\Iaier ( :03) suggests that the membrane 

 was formed by the fusion of a single line of cilia, the cementing 

 substance between the cilia forming a continuous membrane. 

 The basal bodies or "Basalsaum" lie in the angle which the right 

 oral lip makes with the adoral zone so that on the ventral side 

 the right lip protects the basal part of the membrane. PL 34, 

 fig. 7. shows the position of membrane, but owing to the con- 

 traction of the protoplasm the right lip has become a thick 

 rounded mass. The membrane is broadest at the anterior end, 

 ending quite abruptlj^ before it reaches the gullet. 



Bueeal Groove. — At the anterior end on the ventral side of 

 the animal is a three-cornered peristome formed by the edges 

 of the two lips of the adoral zone. The buccal groove differs 

 quite a good deal from the flattened groove of Paramaecium and 



