169] PROTEOCEPHALIDAE—LA RUE 169 



found a widening of the vagina anterior to the ovary. The two dilata- 

 tions of the vagina take the place of the receptaculum seminis. The 

 arrangement of the organs in the interovarial space is typical of the 

 genus. The ovary is a bilobed structure, situated in the posterior part 

 of the proglottid. The ovary does not seem to be made up of blind- 

 pouches, as is true in the ovaries of most of the Taenias. Its outline is 

 somewhat irregular, due to the sack-like processes which may be seen 

 on the plump mass of the lobe. These extend posteriad nearly to the 

 proglottid margin and laterally to the excretory vessels. The vitellaria 

 as in all Proteocephalids are made up of a large number of single folli- 

 cles arranged in long bands extending the full length of each lateral 

 field of proglottid. The vitelline ducts arise in the posterior region of 

 the segment and their course to the interovarial space is like that of 

 other Proteocephalids. The shell-gland is poorly developed. The ute- 

 rus lies in the middle of the proglottid and "As a canal with numerous 

 lateral branches it extends itself through the whole proglottid." "The 

 uterine eggs are round thin shelled structures." Their size was not 

 given. 



This species is readily separated from a large number of species of 

 Proteocephalus on account of its lack of a fifth sucker. Among those 

 species which do not possess fifth suckers this species is most like P. 

 sulcatus which likewise occurs in one of the Siluridae. The latter spe- 

 cies however is much larger as to head and as to observed length. It 

 also has a much larger number of testes. The form of the head is also 

 different. 



PROTEOCEPHALUS SKORIKOWI (Von Linstow) 



[Figs. 152, 177] 



1904: Ichthyotaenia skorikowi von Linstow 1904:18-19 



1911: Proteocephalus skorikowi La Rue 1911:475 



This species was described by von Linstow (1904). La Rue (1911) 

 listed it among other species of Proteocephalus. The following descrip- 

 tion is an abstract from von Linstow 's account. 



The length measures as much as 200 mm., the breadth anteriorly 

 1.14 mm. First proglottids beginning directly behind the scolex are 

 very short. Breadth in middle is 3.75 mm; the length of proglottids 

 here 0.95 mm. Breadth at posterior end equals 3.16 mm; length of 

 proglottids here 1.97 mm. The last proglottid is rounded posteriorly. 

 The scolex is short, 0.67 mm. broad. Von Linstow 's drawing of the head 

 is reproduced (Fig. 152). Suckers measure 0.250 mm. in diameter 



