SOME MAMMALIAN TAPEWORMS. 657 



described, and whicb are referred to elsewhere in the description 

 of this species. Series of longitudinal (sagittal and horizontal) 

 sections brought out the position of the ovaries and their relation- 

 ship to adjacent glands still more clearly. Such sections also 

 showed that the gonads are quite in the middle of the proglottid, 

 i. e. dorso-ventrally. It should be remarked that the double 

 character of the ovary was not always so strongly marked, and 

 that it sometimes lay entirely upon the pore side of the more 

 median (and larger) excretory vessel. Pui'thermore, I have also 

 observed the yolk-gland to lie ufton the median side of the larger 

 excretory tube as well as upon the pore side. There is thvis some 

 variability. 



It is, perhaps, noteworthy that the gonads of the pore side, 

 which consist of the ovary, yolk-gland, and the testes, together 

 occupy about the same space as the gonad and testes only, in this 

 case, of the opposite side of the proglottid. The female gonads, at 

 any rate, are visible very early in the body, within twenty seg- 

 ments, I dare say, of the head. Shortly after their commencement 

 the mass of tissue which is to form ovary, yolk-gland, and, as I 

 presume, ovidvict, vagina, &c., is seen very plainly to extend to- 

 wards the periphery of the proglottid between the two longitudinal 

 excretory vessels, a feature of systematic importance in this group 

 which it is necessai-y to note. In the sexually mature proglottides 

 the ovidvict runs straight from the ovary as a thin-walled delicate 

 tube not easy to see, which is sometimes wider, at least near to 

 its termination, in the ejaculatory apparatus, runs to near the 

 distal termination, and then suddenly nari-ows into a veiy fine 

 tube with thick, darkly-stained walls which, after a very short 

 course, again suddenly widens into a long sac which is as wide as 

 the cirrus sac and runs beside it and below in position. This 

 terminal reservoir is laxly surrounded by what appears to be an 

 adventitious sheath of muscular fibres, which have a circular 

 direction and thus appear cut across ; they are very obvious 

 through their deep staining. This layer of muscles was some- 

 times, but not always, observed to commence with the very thin 

 region of the vagina. The wide terminal region of the vagina 

 bends towards the cirrus sac and again becomes narrow, opening 

 in common with, the latter into the genital cloaca, which is very 

 short. This genital cloaca is quite distinct from an ingrowth of 

 the outer layer of the body which meets it and forms the actual 

 pore ; this has been described in considering the external 

 characters. The cirrus sac, as already implied, is neither wide nor 

 long. The cirrvis was never seen in a protruded condition, but 

 always lay a darkly staining rod within the pouch. The vas 

 deferens, directly it leaves the cirrus sac, is thrown into a large 

 and complicated coil, which reaches for a considerable distance 

 into the interior of the body. I think that it ends in a dilated 

 vesicula seminalis above the ovary ; there is, in any case, a dilated 

 pouch in this region full of sperm, which does not appear to have 

 anything to do with the female ducts. 



