THE UTERUS AND ITS DEVELOPMENT. 445 



canal runs straight forward and sinks into the posterior end of the 

 spherical body. It is much more difficult to demonstrate its connection 

 with the ovary. In favourable preparations, however, it can be seen 

 satisfactorily, and one can convince oneself that the efferent ducts of 

 the tubules finally collect into two transverse branches, which after 

 a short course meet together and then continue in a common duct, 

 which opens into the fertilising canal. Both transverse canals seem 

 to be very extensile ; they are often seen full of eggs, and sometimes 

 even enlarged into a distinct cavity. 1 



The Uterus, however, is also in connection with the shell-gland, by 

 means of a thin duct (0*04 mm. wide), which springs from the gland 

 near the insertion of the fertilising canal, and opens into the posterior 

 end of the uterus. 2 The latter appears, in some respects, as though 

 it were the direct continuation of the canal just mentioned. Like it, 

 the uterus runs straight up the middle line of the joint, continuing 

 nearly to the anterior border, where it ends blindly. Of the subsequent 

 lateral branches there is as yet no trace. The uterus is still a simple 

 tube, with well-defined boundary walls and considerable width (up to 

 0'16 mrn.), so that it is sharply distinguished from the canal which 

 leads to it. The length of the latter is not always the same in the 

 different joints ; it is on the whole but short, so that the lower end of 

 the uterus usually projects some distance between the ovaries. 



What I have just stated in regard to the structure of the sexual 

 organs in Tcenia saginata is primarily true only of the adult joints, 

 those, namely, which are about to copulate, and in which the filling 

 of the uterus is just about to commence. But a similar state of the 

 organs may be observed both in earlier and later stages, as was stated 

 with respect to Tcenia solium in the first edition of this work. In both 

 cases it is necessary to use the staining methods recommended above. 



The Sexual Development is first apparent in joints about 2'5 mm. 

 broad by 0'3 mm. long, 3 which lie at a distance of about 6 to 10 cm. 

 behind the head, and belong to the first half of the third hundred. 

 In these joints there is seen passing from the centre to the middle of 



1 For this reason they are regarded by Sommer, not as efferent canals, but as the 

 median portion of the ovary connecting the two lateral lobes. 



2 Sommer, who confirms the above representation in all points, regards this canal, and 

 also the lower end of the fertilising canal, as a direct prolongation of the oviduct. He 

 gives them both the same name, and would thus have the lower end of the vagina (our 

 fertilising canal) not only opening into the oviduct, but would make the latter coil round 

 the shell-gland which is attached to it, and then run backwards to pass into the uterus. 

 I need hardly note that all these differences are only verbal, and I see little reason to 

 depart from what I have said, especially since the analogous structure in the Dis- 

 tomidae seems hardly to favour Somtner's theory. 



3 I may again note that the accounts of the size and distance from the head are 

 rendered very uncertain by the extreme contractility possessed by these worms. 



