T. B. ROSSETER ON THE ANATOMY OF DICRANOTJENIA CORONULA. 361 



are formed during the development of the scolex in the 

 cysticercoid stage. If the cysticercus when taken from its 

 nurse is treated with simmering nitric acid, the encysted scolex 

 escapes through the eversion of the invaginated portion of the 

 cyst; by this process in mature scohces they appear like fine 

 threads. 



Irrespective of the muscular structure already described, each 

 proglottis is furnished with a series of trellis-work muscles 

 running from the distal to the proximal lateral border. They 

 are smooth muscle fibres, and have a diameter of 0'003 mm. 

 (Fig. 3). They are deeply stained by the action of hsematoxylin 

 in chromic- acid specimens. The porose muscles have an angle 

 of 30° and the aporose an angle of 00°. I have not been able 

 to trace any connection between these muscles by the aid of 

 spindle-cells from one proglottis to the other, consequently I look 

 upon them as independent muscle fibres. It is this muscular 

 trellis- work which adds so much to the density and tenacity of 

 the sexually mature portion of the strobila, for it is not developed 

 in the earlier segments. 



Placed equidistantly round the basal portion of the rostellum, 

 but imbedded in the tissue, are four palmate ganglionic bodies. 

 Each ganglion is split up into five digital parts, with a commissure 

 between each digit. The lower portion of each ganglion tapers 

 to a thin cord. Each of these cords attaches itself to an 

 annule, or ring, which makes a circumference of the interior of 

 the scolex, but does not impinge on either of the suckers. This 

 ring in situ appears to be a homogeneous mass, but is really made 

 up of four annular cords. From these rings proceed, posteriorly, 

 as outgrowths, four very fine cords, which proceed downwards, 

 both ventrally and dorsally, near the lateral margin, the whole 

 length of the strobila. As they emerge from the scolex, and through 

 the neck and early segments of the strobila, they are straight 

 narrow cords ; but with the growth of the proglottis they develop, 

 become broader, and undulatory or wavy in their character 

 (Fig. 20). They do not lose their individuality in the sexually 

 mature proglottides, but in the uterine segments they are 

 untraceable. This wavy condition coincides vrith Von Linstow's 

 wavy nerve-cords of Tcenia depressa ; and, although I origin- 

 ally thought that these palmate bodies were " retractor 

 muscles," and described them as such, I am now convinced by 



