254 CILIATE FIBRILLAR SYSTEMS 



of the oral plug; and (4, 5) two ventral fbr/ls extending downward 

 and ending freely in the endoplasm. It was observed that the mem- 

 branelles not only serve the organism in feeding and in locomotion, but, 

 during periods of binary fission, function in the building of the lorica. 

 In addition to their fibrillar connection with the motorium, each mem- 

 branelle is supplied with three large basal bodies. 



Method 



Fixative: Schaudinn's (aqueous and alcoholic), 90° C. 

 Stain: Iron-haematoxylin (whole mounts and sections). 



Tintinnopsis nucida (Campbell, 1926). — The somatic ciliation is con- 

 fined to the column and forms in longitudinal rows along the myonemes. 

 These showed basal granules, but without fibril connection. The myo- 

 nemes are ectoplasmic structures, arranged longitudinally and un- 

 branched. Anteriorly, they extend to the reflexed margin of the collar 

 and possibly connect with basal granules of the adoral membranelles; 

 posteriorly, they fade out. 



At the base of each adoral membranelle are three basal granules con- 

 nected by fibrils. Through this triangular base passes the adoral motor 

 fbril. Three oral membranelles (flat plates of fine cilia) follow the 

 spiral of the gullet. Each oral membranelle ends in a distinct basal body. 

 The ciliary membrane (undulating membrane of unusual construction), 

 which functions in house-building and repair, is connected through its 

 basal granules to the adoral fiber. A retractile tentaculoid is found be- 

 tween each adoral membranelle. Tentaculoids, accessory combs, and 

 trichocysts have no known fibrillar connection. 



The motorium is located in the ectoplasm of the ventral wall of the 

 column. From it arise directly (1) the adoral fiber (granular), which 

 connects with the adoral membranelles, the oral membranelles, and the 

 ciliary membrane; (2) two dorsal fibers, extending into the ectoplasm 

 adorally, where they end freely; and (3) the ventral fiber, which extends 

 downward and also ends freely in ectoplasm. The circumesophageal ring 

 is connected to the motorium indirectly by a single fiber. Short fibers 

 from the ring surround the gullet. 



Methods 



Fixatives: Schaudinn's, 90° C. 



Stain: Heidenhain's iron-alum haematoxylin, aqueous and alcoholic. 



