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the ventral commissure (Figs. 1, 2 coms.v.). These two commissures 

 with the two ganglia constitute an elongated ring embracing both of 

 the longitudinal excretory tubes. In this way the lateral nerve of each 

 side of the body is connected by a double, or ring-like, commissure 

 with its fellow of the opposite side near the posterior margin of each 

 proglottis. These two commissural nerves are band-like, being flatte- 

 ned dorso-ventrally ;^ along their whole length occur ganglionic nerve 

 cells, either singly or grouped into clusters at the places where nerve 

 fibres are given off from the commissures. 



The two commissural nerves are united with each other by means 

 of two dorso-ventral nerves, — one near each margin of the proglot- 

 tis, — which are situated close to the median side of the longitudinal 

 excretory tubes. I have named them the dorso-ventral connectives 

 [con't.d.-v.]; one of these connectives, together with the corresponding 

 posterior lateral ganglion and the corresponding ends of the two com- 

 missural nerves, constitutes a small nerve ring which closely encircles 

 the longitudinal excretory tube immediately behind the transverse 

 excretory tube (Figs. 1 and 2). 



In the lateral nerve trunk, about mid-way between the posterior 

 lateral ganglion of each proglottis and that of the preceding proglottis, 

 there is a second enlargment containing ganglionic cells, the anterior 

 lateral ganglion (Fig. 1 gn.l.a.). It is situated near the region where 

 the lateral nerve crosses the sexual ducts in their passage to the 

 gonopore. 



From this ganglion there arises a single nerve trunk, which passes 

 obliquely inward and dorsad for a short distance and then divides; one 

 branch turning outward becomes the external genital nerve (Fig. 1 

 n.geti.ex.) and is distributed to the region of the gonopore, while the 

 other branch continues its inward course, becoming the internal ge- 

 nital nerve (Fig. 1 n.ffen.i.), which is distributed to the ovaries and 

 uterus. 



Upon both dorsal and ventral commissures, there are two enlar- 

 gements containing characteristic ganglionic cells. These ganglia are 

 situated about mid-way between the posterior lateral ganglion and the 

 median plane of the proglottis. The ganglia of the dorsal commissure 

 which occupy the right and left halves of the proglottis I have called 

 the right and left dorsal ganglia, respectively (Figs. 1, and 2 gn.d.dx. 

 and gn.d.s.]] those of the ventral commissure, the right and left 

 ventral ganglia, respectively [gn.v.dx. and gn.v.s.]. From each of 

 these ganglia there arise two nerves, one running forward, the other 

 backward; together, they traverse the greater part of the proglottis, 

 and I believe that through them the commissural ganglia of one pro- 



