248 RECORDS OP THE AUSTRALIAN MUSEUM. 



medulla. The dorsoventral fibres are more distinct and pass 

 between the longitudinal bundles and through the medulla. 



The nervous system is not well marked. There appears to be 

 only one longitudinal fasciculus, this being situated on the outer 

 side of each main longitudinal excretory vessel. I cannot make 

 out the various concomitant fasciculi described in some Taeniadse. 



The excretory system consists of the usual parts. The outer 

 longitudinal vessel has a much wider lumen than the inner one, 

 the former representing the dorsal and the latter the ventral 

 vessel. Their relative position varies somewhat in the segments 

 but the inner trunk is generally placed more ventrally. Con- 

 necting the outer trunks, there is in the posterior part of each 

 proglottis, a wide transverse commissural canal. There do not 

 appear to be any valves present. 



Of the genital system, the earliest trace appears in about the 

 sixtieth-segment, as a cord of cells representing the rudiments of 

 the cirrus sac and vas deferens. The testes are well developed in 

 the hundredth. Meanwhile, the vitelline gland, ovary and vagina 

 have made their appearance. In the next eighty proglottids 

 both sexes are mature. Beyond this the testes disappear rapidly, 

 the segments becoming full of developing ova. The final prog- 

 lottids are densely crowded with eggs containing hexacanth 

 embryos (onchospheres). 



The genital apertures are marginal and unilateral, being on 

 the right side. Very rarely there may be an opening on the left 

 instead. There is no genital eminence, the position of the aper- 

 ture only being visible in stained and mounted preparations 

 unless the cirrus be more or less everted. It is situated near the 

 junction of the anterior third and posterior border of the over- 

 lapping portion of the preceding segment. 



The testes are situated in a single layer lying nearer the dorsal 

 surface. They gradually iuci'ease in number, the more anterior 

 segments possessing about fifty, later segments about sixty. They 

 are thus fairly numerous. Their shape is subspherical, the average 

 diameter being about thirty-seven micra. They are well within 

 the medulla and occur more abundantly in the middle and 

 posterior region of each proglottis, comparatively few being 

 present in the anterior third. Arising from each testis is a 

 rather strong vas efferens which joins with others to form the vas 

 deferens at about the middle of the anterior part of the segment, 

 in front of the ovary. This passes on laterally towards the right, 

 becoming enlarged and coiled near the neighbourhood of the 

 excretory vessels. It is here strongly muscular. After passing 



