218 ILLINOIS BIOLOGICAL MONOGRAPHS [218 



OPHIOTAENIA NATTERERI (Parona) 



[Figs. 139, 194, 195] 



1901 : Ichthyotaenia nattereri Parona 1901 :4-6 



1908: Ichthyotaenia nattereri Schwarz 1908:17-19 



1911 : Ophiotaenia nattereri La Rue 1911 :481 



Specific Diagnosis: Characters of genus. Length 75-250 mm., 

 maximum breadth not over 1 mm. Scolex unarmed, rounded but not 

 spheroidal, not easily distinguished from the neck. Diameter of scolex 

 0.240-0.250 mm. Suckers four in number, circular, cavity deep, margin 

 thick, diameter of suckers 0.120-0.150 mm. No rostellum and no fifth 

 sucker. Neck long, 7-8 times the length of the head. First segments 

 broader than long, more or less indistinct. Mature proglottids nearly 

 quadrate. Ripe proglottids longer than broad, length of same up to 2.0 

 mm., breadth 0.33-0.50 mm. Last proglottids readily detached. Seg- 

 mentation distinct. 



Genital aperture irregularly alternating, situated somewhat ante- 

 rior to middle of proglottid margin. Testes 80-100, 0.042 mm. in diame- 

 ter, situated in two lateral fields. Vas deferens a thick mass of coils 

 extending even past the middle of the proglottid. Ductus ejaculatorius 

 much coiled. Protruded cirrus slender, heavy at base, about 0.20 mm. 

 long. Cirrus-pouch about 0.265-0.280 mm. long, extending from 1 / 3 - 2 / 7 

 across proglottid breadth. Vagina anterior or posterior to cirrus-pouch. 

 Sphincter vaginae present. Uterus, when fully developed, possessing 

 15-20 lateral pouches on either side. Eggs provided with three mem- 

 branes. Outer membrane covered with fine hooklets. Eggs 0.024 mm. 

 in diameter. 



Habitat: In intestine of Coluber sp. from Liguria, a district of 

 Italy. The material was collected by Parona in December, 1897. 



This species was first described by Parona (1901:4-6) but the de- 

 scription was not accompanied by drawings. Schwarz (1908:17-19) 

 delineated and redescribed the species, using Parona 's specimens. La 

 Rue (1911:481) included this form in a list of species of Ophiotaenia. 

 The data upon which this description is based were secured from the 

 descriptions of Parona (1901) and Schwarz (1908), and from observa- 

 tions made upon slides prepared from type material which Professor 

 H. B. Ward secured from Professor Parona. 



