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in paraffin. By this treatment, nervous tissue is differentiated from 

 muscular and connective tissue, the nerves being colored greyish blue, 

 whereas the more highly refractive muscles become brownish, and the 

 connective tissue remains paler than either of the two other tissues. 



None of the previous workers upon the nervous system of Cesto- 

 des have been able to find any transverse connections between the 

 large longitudinal nerves of the two margins of the proglottides. Even 

 Blochmann and Zernecke have not shown any transverse con- 

 nection, and indeed both observers have denied that such connections 

 exist in the forms which they have studied; but with vom Rath's 

 killing mixture, I have been able to demonstrate in both Moniezia ex- 

 patisa and M. pianissima certain well defined commissures. 



The lateral nerve trunk (Fig. 1 n.l.) of these Cestodes is elliptical 

 in cross section, the longer diameter having a dorso-ventral direction. 

 The course of the nerve, as is well known, is nearly parallel to the 

 longitudinal excretory tube (Fig. 1 va.exclg,). Near the posterior 

 end of each proglottis the lateral nerve becomes enlarged, forming a 

 distinct ganglionic mass, which I have called the posterior lateral 

 ganglion (Fig. 1 gn.l.p). The dorso-ventral diameter of this ganglion 

 is somewhat greater than the diameter of the longitudinal excre- 

 tory tube, but its antero- posterior extension is still greater, whereas 

 in the direction of the transverse diameter of the proglottis it measures 

 considerably less than in the dorso-ventral direction. 



There are two kinds of ganglionic cells in these enlargements. 

 The larger cells occupy the central portions of the ganglion; the 

 smaller ones are at the periphery. A description of these, with other 

 histological details, will be given in a final paper accompanied by 

 illustrations. 



From the outer side of each of these ganglia arises a large nerve 

 (Fig. 1 n.marg.), which passes off from the ganglion towards the mar- 

 gin of the proglottis, — at first in a direction nearly perpendicular to 

 the course of the lateral nerve, — and then turns with a broad curve 

 and runs forward for about two thirds or three-fourths of the length 

 of the proglottis. This nerve is distributed to the lateral margin of 

 the proglottis and gives off nerve fibres along its entire length. I have 

 named it the marginal nerve. From the same region of the ganglion 

 and from the beginning of the marginal nerve arise several small nerves, 

 which are distributed to the marginal portions of the posterior end of 

 the proglottis. In addition, there arises from the posterior outer mar- 

 gin of the ganglion a short, rather stout nerve, which is distributed to 

 the margin of the anterior portion of the following proglottis. Although 

 this nerve takes a course which would suggest that it may anastomose 



