192 TAPEWORMS OF HARES AND RABBITS- STILES. 



but gradually the uterus develops to such an extent that it suppresses 

 all the genital .ulniids. The cirrus pouch becomes indistinct, but the 

 vagiuii can be traced in nearly all segments. 



As the uterus increases in size it gives rise to i)roxinial and distal 

 brandies, but the latter are far less regular than those of tlu; luuopean 

 C. pcrtiiiiifa. In tlie posterior segnuMits it is gencially difficult to dis- 

 tiiiguisli the two uteri. Tlie ova measure <>() to 04 // in diameter: the 

 ball) of the ])yriforni body, 12 to 16 //. This is the s])ecies fvar. (oif/KNtd) 

 ujxin which my i>aper, "A double-pored cestode with occasional single 

 pores'' was based, and since writing that note another case of the same 

 variation was noticed. On account of the numerous variations in 

 the position of the genital i)ores, uterus, etc., noticed in the specimens 

 studied, I proposed to name the worm Ctcitotivnui r<iriahUis. 



Larval staije. — The young specimens described on i)age 201 were col- 

 lected in the same locality as the species here described, and from the 

 same host; and it seems jtrobabh* that the unarmed young mentioned 

 on page 2(H are the young of either V. ranahili.s or C. perplc.ni. 



DiagnoHiH. — Cittotwnia v<(riahilis (Stiles, 1895), Stiles & Hassall, 1890. 

 (American rei)resentative of C. pn-tinata.) Strobila attains 1<>(> to 

 180 mm, in length and 10 mm. in breadth. Head small, about 0,3 to 

 0.0 mm. in lueadth ; it may or umy not be defined from the neck accord- 

 ing to contraction. Neck very short, segmentation beginning almost 

 immediately back of the head; segments always much broader than 

 long. Genital anlagen appear very early, about ."» to 10 mm. from the 

 head. Genital pores double, in about the middle third of the lateral 

 margin. Male organs: Testicles about 00 to 100 in each segment, con- 

 lined between the ovaries to the dorsal portion of the distal half of the 

 median field; cirrus jiouch about 0.4 mm. long, narrow and very indis- 

 tinct, lying dorsally of the vagina on both sides of the segment. Female 

 organs: Ovary, shell gland, and vitellogene glan<l rescnd)le the corre- 

 sponding organs of Moniczia: they lie median of longitudinal canals, 

 about 1..") mm. from the lateral margin; the vagina is rather distinct, 

 lies ventrally <tf the cirrus pouch, and for about 0.5 nnn. from the pore 

 it is surrounded by deeply staining cells; uterus may be double or 

 single (in the same specimen) and nia,\ i)roduce proximal and distal 

 branches; ova 00 to 04 // in diameter; bulb of pyriform body 12 to 10 //, 

 Longitudimd nerve about 0.0 mm. from the lateral margin; ventral 

 canal large with thin lining; dorsal camil much suudler than ventral 

 canal, dorso-median of ventral canal, with thick lining; transverse 

 canals connect ventral camUs fno injections made for secondary longi- 

 tudinal canals], (ienital ducts and uterus ]»ass from nu-dian to lateral 

 field on the dorsal side of the longitudinal canals an<l nerves. 



Host. — Cottontail Eabbit {Lepits Kylraticu.s), by Hassall; Marsh Hare 

 [fj. pali(sfris), by .Mills. 



Types. — Uureau of Animal Industry, ("estode series No. 117 desig 

 nated as type and (k-posited in tlu' (nited States National Museum. 

 Paratyi)es distril)utcd as follows: Collection of lUireau of Aniuuil 



