70 ILLINOIS BIOLOGICAL MONOGRAPHS [70 



those species by the presence of a functional fifth sucker which those 

 species lack. P. pinguis is quite different from the European forms 

 which have fifth suckers. These are P. percae (O. F. Miiller), P. fallax 

 La Rue, P. duhius La Rue, P. cernuae (Gmelin), P. longicollis (Rud.). 

 It differs from them in size of body, size of suckers and of proglottids, 

 in the relative length of cirrus-pouch, in the size of the embryos and in 

 the number of testes. 



PROTEOCEPHALUS FALLAX La Rue 

 [Figs. 23, 56, 57, 150, 170, 178, 179] 



1884 

 1884 

 1892 

 1892 

 1905 

 1905 

 1911 



Taenia ocellata Zschokke 1884:13-14, in part ( ?) 



Taenia longicollis Zschokke 1884:14-15 



Taenia filicollis Kraemer 1892:535-555 



Taenia ocellata Kraemer 1892:572-576 



Proteocephalus ocellata Nufer 1905 in part( ?) 



Proteocephalus longicollis Nufer 1905 in part( ?) 



Proteocephalus fallax La Rue 1911:475-477 



Specific Diagnosis : Characters of the genus. Cestodes quite small. 

 Length up to 100 mm. Maximum breadth as much as 1.20 mm. Head 

 somewhat globose, 0.150-0.200 mm. in breadth by 0.105-0.150 mm. thick. 

 Head well set off from neck. Suckers situated near broadest zone of 

 head. Diameter of suckers 0.064-0.085 mm. Diameter of sucker opening 

 about 0.040 mm. Fifth sucker present, functional, about 0.058 mm. in 

 diameter. Neck narrow, length 2-6 mm. First proglottids quadrate or 

 longer than broad. Mature proglottids quadrate or broader than long, 

 0.34-0.46 mm. broad by 0.34 mm. long. Ripe proglottids longer than 

 broad, rarely measuring as muclj as 1.19 mm. broad by 1.36 mm. long. 

 Segmentation indistinct, margins smooth. 



Genital sinus marginal, alternating, situated near middle of the 

 proglottid. Testes 30-35 in number, irregularly scattered in single layer 

 between vitellaria and anterior to ovary. Diameter of testes 0.037-0.060 

 mm. Cirrus-pouch in mature proglottids 0.196-0.255 mm. long, in ripe 

 proglottids 0.37-0.42 mm. long. Ratio of length of cirrus-pouch to 

 breadth of proglottid 1:3-1:2. Cirrus and ductus ejaculatorius nearly 

 straight. Length of protruded cirrus 0.026 mm. Vas deferens forming 

 a mass of coils in middle of proglottid. 



Female organs typical of genus. Vaginal opening anterior to cirrus- 

 pouch. Vaginal sphincter weak. Ovary bilobed, lobes solid, thick, elon- 

 gated ovoidal in form. In ripe proglottid ovary lies in triangular area 

 between pouches of uterus. Vitellaria lateral, sparse. Uterus ventral. 



