SEXUAL ORGANS OF THE PRISMATIC FORMS. 455 



reports of his Tcenia from the Hottentot does not exist ; I have 

 reason to believe that the account was based upon error. Nor are 

 supernumerary pores ever observed on the lateral margins of the 

 wings. 



The main stem of the uterus runs up the line where the two 

 wings are united to the ridge in a position which we must regard as 

 the morphological axis of the prismatic worm. It has through- 

 out the ordinary structure, and sends out numerous branches towards 

 the three angles, though these are indeed somewhat fewer than usual. 

 The longitudinal ridge which represents the somewhat less developed 

 median wing has the fewest and shortest branches. 



But this longitudinal ridge is, as we have noted, the seat of the 

 generative openings, to which the ducts become subsequently con- 

 nected. I may omit the cirrhus-pouch and its contents ; they show as 

 few peculiarities as the generative cloaca. But it is otherwise with 

 the vas deferens, which, after issuing from the cirrhus-pouch, becomes 

 twisted together into a close coil of considerable size, which embraces 

 like a crescent one side of the longitudinal vessel running behind the 

 cirrhus, and then, still coiled, continues to the uterus, from which 

 it bends for some distance backwards. The 

 vagina lies on the same side, but is deeper, and 

 is turned more to the outside. It is difficult to 

 follow it posteriorly, but it is tolerably certain 

 that it gradually changes its original lateral 

 position for a median one, and runs backwards 

 at a short distance behind the longitudinal 

 vessel, between the latter and the coiled vas de- 

 ferens, or the uterus. The lower end, with the 

 receptaculum and the shell-gland, I have not been 

 able to see distinctly. But the ovary and yolk- 

 gland are present, and their lateral halves belong 

 to the two wings of the triangular joint, and to FIG. 261. Prismatic 

 that aspect which we called the female surface- Pgl>ttis in transverse 



. -i t ,.-, . , . section through the porus 



Ihe longitudinal ridge contains only the median genitalis. ( x8.) 

 portion of the germ-producing organs. The 

 numerous testes, filled like the vas deferens with semen, are embedded 

 in the interior surfaces of the two wings. 



Besides the above-described prismatic proglottides, Professor 

 Auerbach also sent me three isolated joints of so strange a structure 

 that a close investigation was required in order to understand them. 



On superficial inspection, they appeared as three-cornered de- 

 pressed cones or hollow pyramids about 8 mm. high, by as many 

 broad. The side walls had also the same size, and were united 



