Art. VII. — On the Structure of the Vibratlle Tags 

 or Flame Cell in Rot if era. 



By J. SHEPHARD. 



(Plates XI. and XII.). 



[Eead 11th August, 1898.] 



The somewhat doubtful tone of the remai'ks on the flame 

 cell or vibratile tags of Rotifera in the second volume of the 

 " Cambridge Natural History" led me to examine these organs 

 in Euchlanis dilatata and Brachionus pala, species favourable to 

 a study of the excretory system, particularly the former. Having 

 these two forms at hand in a cultivation from di'ied mud, for a 

 considerable time, there was ample opportunity to examine them, 

 and as a result a definite conception of the structure of the organ 

 was attained, and, being subsequently confirmed by investi- 

 gations on several species, T was led to record my i-esults in the 

 hope of contributing towards a settlement of the vexed question 

 as to their exact structure. 



The flame cells are appendages of the lateral canals which run 

 up each side of the body, and are regarded as the excretory 

 organs in the Rotifera. 



The outlines of the tags examined, in different aspects I 

 found in general agreement with the description by Dr. Hartog^ 

 and with the descriptions and figures of various other authors. 

 In front view the outline is more or less fan shaped, and at right 

 angles to this it has a narrow elongated form very nearly equal 

 in width from end to end. In the internal portions of the tags 

 I found appearances not altogether consistent with any of the 

 figures and descriptions to which I have had access. 



Examining a specimen of E. dilatata when compressed so that 

 the tags were fixed, some of them were found presenting the 

 narrow and others the fan-like aspect. When seen in the former 

 position, a solid plug occupied the distal end, and to it, as shown 



Cambridge Nat. Hiat., vol. ii., p. 213. 



