TAPE-WORMS OF THE SUB-FAMILY AVn'ELLININ.E. 365 



hand, every stage of the development of the flame-cells 

 observed by me in Avitellina has served to verify Bugge's 

 statements. 



The fully developed flame-cells do not present any remark- 

 able differences from those figured and described by otlier 

 authors, except that they almost regularly contain a small 

 corpuscle in the plasma, whose nature I have not been able to 

 identify (,i'). The cells always occur in groups of four, most 

 frequently in the medullary substance, very rarely in the 

 transverse muscle, hardly ever exterior to the muscle. They 

 consist of a cell (figs. 34 and 37) with granular plasma, 

 usually with iriegular, star-shaped outline ; the nucleus 

 contains a nucleolus and a varying number of chromatin 

 bodies. The flame usually stands vertically to the cell, more 

 rarely tangentially ; the flame is often quite close to the 

 nucleus, but it is sometimes separated from the main portion 

 of the cell and the nucleus by a longer or shorter "neck " of 

 plasma. The flame arises from a basal plate, a meniscus- 

 shaped body with its concave side turned towards the flame, 

 its convex side embedded in the cell. The flame itself consists 

 of cilia. The funnel is widest a little way from its base; 

 near its middle it is suddenly thickened, a ring of the 

 substance of the funnel projecting into and somewhat con- 

 stricting the lumen. The capillary usually runs straight in 

 the same direction as the funnel for about once or twice the 

 length of the funnel, and then bends suddenly to one side; 

 after a short distance it bends again to resume its original 

 direction. The capillaries can often be followed for a con- 

 siderable distance, and frequently present a very devious 

 course. It is interesting to note that the flame-cells invari- 

 ably lie at right angles to the longitudinal axis of the worm, 

 so that they fall within the plane of a transverse section. 

 They are fairly frequent in the scolex as well as in the strobila, 

 but do not occur in the suckers. 



The flame-cells have long been recognised to be unicellular 

 glands (Pinter, Lang, Bugge, Blochmann), and the capillaries 

 to be their ducts ; both the flame-cells and the uephrocytes 



