318 



THE ANATOMY OF CESTODES. 



in the following descriptions. The latter, however, refer mainly to 

 the forms with mesially situated porus, and especially to the genus 

 Dibothrium, or, as it is generally called, Bothriocephodus.' 1 - 



As to the male organs (Fig. 170, A) but little can be said. Anatomi- 

 cally and histologically they resemble the same organs of Tit'iiiadib, and 

 indeed they only differ from them in particulars which are determined 

 by the ventral position of the porus genitalis. Thus the vas deferens 

 starts from the base of the cirrhus-pouch, which is perpendicularly 

 situated upon the ventral surface, and runs down the middle of the 

 joint, under the dorsal surface, as a tolerably wide canal, bending 

 sometimes to the right and sometimes to the left of the middle line. 

 Whether the bulbus musculosus, which in Bothriocephcdus latus lies 

 close behind the cirrhus-pouch, is of wide distribution, cannot be 

 determined without further investigation, but one feels tempted to 

 connect its presence with the above-mentioned position of the cirrhus- 

 pouch, and to interpret it as a pumping apparatus, designed to remove 

 the difficulties attendant upon the transference of the semen, with 



- 



FlQ. 170. Male (A) and female (B) sexual organs of Bothriocephalus 

 latus. ( x 20.) 



which the seminal duct is itself abundantly filled. This filling takes 

 place exclusively at the posterior end, into which the vasa efferentia 



1 Besides Eschricht's classical work on Bothriocephalu* lotus, which we shall often 

 have occasion to quote, it is especially to the already mentioned treatises of Stieda and of 

 Landois and Sommer that we owe our increased knowledge of the structure of the sexual 

 apparatus in Bothriocephalus. The description which I have given in the first edition of 

 this work, although expressing even in details many of our present views, contains a 

 number of errors. These are of course corrected in this edition, and throughout, on the 

 strength of my own observations, which corroborate the results of Stieda and Sommer 

 and Landois. 



