VARIOUS ABNORMALITIES. 



713 



Joints not unfrequently occur in which the external coverings of 

 the uterus have been burst and the eggs liberated ; long chains of 

 open or split joints are also occasionally seen. In contrast to the 

 somewhat similar phenomenon seen in the Tcenice (p. 457), this burst- 

 ing seems here to be due in most cases to a superabundant accumula- 

 tion of ova within the uterus. The ripe joints of Bothriocephcdus 

 indeed usually liberate their contents in the normal way the ova 

 are generally found in large numbers in the faeces of the host but 

 cases are readily conceivable in which the liberation has not kept pace 

 with the production. 



The Abnormalities exhibited by Bothriocephalus 

 latus include others than this bursting, which, in 

 consequence of the shortness of the joints, not un- 

 frequently appears as a distinct cleft through a 

 whole series. The doubling of the genital aper- 

 tures even is quite a common occurrence. I have 

 scarcely examined a single specimen without ob- 

 serving a greater or smaller number of adjacent 

 joints with this malformation. These segments 

 are usually further marked by their form. The 

 limiting margins are not straight, but divided in 

 the middle by a sort of step-like interruption into a 

 right and a left half, which are on different levels. 

 Portions are sometimes even separated by a furrow, 

 which extends from the middle corner of the an- FIG. 373. Series of 

 terior margin diagonally to the superior corner of J| nts with double g eni - 



. 6 .-it i ,.1 T tal apertures. 



the posterior margin. But even where the division 

 is not externally manifest, its presence can be readily detected by the 

 use of a compressorium. A clear line of demarcation in the direction 

 above mentioned is then observable, plainly showing that each half of 

 the joint has its special genital aperture. And more than that, one 

 can see that each of the halves is furnished with a more or less perfect 

 set of genital organs. Most distinct are the uteri, both of rosette-like 

 form as usual, except that the horns directed inwards are distinctly 

 shorter than usual. It may also happen that the two uteri are of 

 unequal size, one having grown at the expense of the other. As with 

 the internal uterine horns, so also the other portions directed towards 

 the middle line are atrophied. One cannot, however, deny that a true 

 duplication has taken place, that there is really a double chain, whose 

 joints have united by their adjacent margins, with concomitant degene- 

 ration of the approximated lateral areas. That the joints are wedged 

 alternately into one another is of subordinate morphological impor- 

 tance. This condition is genetically explained, and indeed the whole 



