NEW AVIAN TAPEWORM. 219 



in fact, paruterine organs. This is not the case with the sacs of 

 eggs in Oliditceuia. 



We may aV)stract from the foregoing iiccount of the anatomy of 

 this worm the following resume of its structural characters: — 



Length about 3 inches ; greatest breadth 4 mm. Scolex with 

 feebly developed rostellum with a marginal double circle of very 

 numerous and small hooks. Suckers unarmed and rather large. 

 Neck present and short. Proglottids broader than long, except at 

 the extreme end of the body, where they become rabher longer 

 than broad. Completely mature proglottids almost spherical, 

 except for the frill which overlaps the following proglottid. Two 

 excretory tubes on each side, of which the ventral are veiy wide 

 and the dorsal narrow ; the two are at times parallel, but occasion- 

 ally the dorsal tube is really somewhat dorsal in position. Ventral 

 vessels joined by a wide ci'oss-trunk at the posteiior end of each 

 proglottid. Generative pores alternate irregularly; the generative 

 ducts pass between the dorsal and ventral trunks of the excretory 

 system. The generative pores are not borne at the end of out- 

 growths of the proglottid. The testes lie at the extreme end of 

 the proglottid and form a vertical wall of over 200 separate 

 gonads, which, however, are included in a mass of medullary tissue 

 rather difterent from the medullary parenchyma generally. The 

 sperm-duct forms a large coil, and is also slightly coiled within 

 the rather large cirrus sac. In the latter the actual cirrus is 

 short and is connected with a wider (? eversible) tube also con- 

 tained within the cirrus sac. The cloaca genitalis is deep. The 

 ov;vry and vitelline gland lie in front of the testes. The vagina is 

 furnished with a large reeeptaculum seminis. It opens into the 

 cloaca genitalis behind and iit right angles to the cirrus sac. The 

 uterus lies in front of the ovary, and in mature segments the 

 whole reproductive system is restricted to tlie posterior fifth or so 

 of the proglottid. The uterus is a narrow transverse tube, wider 

 at the two sides. La,ter it is broken up into several more or less 

 spherical compartments. The eggs are imbedded, within the 

 uterus, in a mass of cellular tissue whose origin is uncertain, and 

 which later loses its celhdar character. 



We have now to consider whether the species described in the 

 present communication can be referred to any known genus or 

 whether it will be necessary to form a new genus for its reception. 

 The abstract of the anatomical characters that has just been given 

 shows that the worm is undoubtedly a member of the lai'ge family 

 Hymenolepididse or perhaps of the Davaineidae. This conclusion 

 need not be pi-oved in detail. Furthermore, it is clear that the 

 features which distinguish it, viz. the following assemblage of 

 characters, necessitate its inclusion in one of the genera Mono- 

 pylidium, ChoanoUenia, or Anomotcenia of the Hymenolepididse, 

 or to a new genus altogether. These characters are; — Armed 

 rostellum and unarmed suckers ; large number of proglottids ; 

 alternate generative pores ; absence of paruterine organs ; testes 

 behind ovai'ies ; breaking up of uterus in ripe segments ; and in 



