398 T. B. ItOSSETER ON HYMENOLEPIS ACICULA SINUATA, 



these one was but partially so. In the case of the other the 

 telescopic truncated cone that was everted did not approach or 

 have any tendency to approach the vestibule of the vagina with 

 a view to copulation, but was pushed slightly forward in advance 

 of the vagina. How, then, did the spermatozoa reach the vagina 

 and the vaginal canal in order, as it had done in previous and 

 succeeding segments, to fill the receptaculum seminis ? It natu- 

 rally occurred to me that in the absence of a cirrus there must be 

 a ductus efferentia in some form to carry the sperm on to the 

 vagina.* Patient research, careful manipulation of the light, 

 and the aid of an immersion objective enabled me to determine 

 that the membranous tissue which attaches the male organ to the 

 female runs round the circular rim of the funnel and thus forms 

 a conduit or ductus efferentia to the emissary pore (totally 

 distinct from the dermal wall of the cul-de-sac) and in a semi- 

 circular form attaching itself at its opposite end to the periphery 

 and costals of the vestibule. Along this semicircular conduit the 

 spermatozoa, which could be traced in the duct, are propelled into 

 the vestibule, through the narrow vagina, thence into the lumen 

 and along the vaginal canal into the receptaculum seminis. Thus 

 in this species of tapeworm no actual act of coition takes place, 

 but merely impregnation in its primitive form of transmission. 

 In the place, therefore, of an elaborate male copulatory apparatus 

 we have a simple infundibuliform canaliculus genitalis, f 



There is another characteristic of this tapeworm which requires 

 consideration and explanation. There are ten hooks on the 

 rostellum, these being in number and in eveiy other respect 

 the counterpart of those possessed by Taenia anatina. Indeed, 

 so much so in this case that had these hooks been placed before 

 me without any portion or description of the worm from which 



* It must be borne in mind that I had but this one specimen to work 

 upon, and that it had been fixed, stained with haematoxylin and safranin, 

 and permanently mounted in glycerine. 



f This method of fructification is analogous with that which exists in 

 the Holostomidae, viz. II. excisum, and goes to prove the affinity that 

 exists morphologically between the Trematoidae and Cestoidae. 



