Dicotylidae Monticelli, 1903; Sphyranurinae Price, 1939. 



Polyopisthocotylinea^ of middle sizes. The attaching disc of the 

 larvae and of the adult individuals bears 16 edge hooks, 2 middle hooks, and 

 2 powerful suckers. The anterior end has a large buccal suckers. The 



eyes are absent. The intestinal trunks are simple without outgrowths, they 

 merge at the posterior end. The ovary is flask-shaped, the testes are 

 numerous. The uterus is absent; the obtype contains one egg. Vaginal 

 ducts are paired; they terminate blindly without opening outside. 



Parasites of caudate Amphibia. 



Type and only genus, Sphyranura Wright, 1879. 



This family was first established by Monticelli (Monticelli, 1903) 

 but he gave it a name which did not correspond to the name of the only genus 

 which enters it, in connection with which, according to the rules of nomen- 

 clature Poche (Poche, 1925), completely correctly, gave the family its 

 present name. Later Price (Price, 1939) transferred this family to the 

 rank of a subfamily of Polystomatidae which, even though it was accepted 

 by a number of subsequent authors including Sproston (Sproston, 1946), 

 nevertheless cannot be considered correct. Just as in our work in 1937 

 we are completely in agreement with Poche that Sphyranuridae is an 

 independent family for this is not only substantiated by the peculiarities 

 of structure in the adult fornns but also by features of the embryology, 

 inasmuch as the differences between the larvae of Polystomatidae and 

 Sphyranuridae are very important (see pages 186 and 190 ). It would be 

 very tempting to consider Sphyranuridae as the more primitive group in 

 comparison with Polystomatidae; however, the peculiarities of this group 

 have a secondary nature, in connection with which the number of suckers 

 of the attaching disc underwent indubitable oligomerization. One of the 

 proofs of the origin of Sphyranuridae from Polystome-type ancestors is 

 the presence of the closed vaginal ducts which play the role of peculiar p, 402 



repositories of the sperm in this group just as is observed during the period 

 of reproduction in Polystoma integerrimum Froelich, where the inflated 

 part of the vaginal ducts is used for this purpose (see page 84). 



Subclass Oligonchoinea Bychowsky, 1937. 



Monogenoidea^ having larvae with 10 edge hooks. As an ex- 

 ception the edge hooks can be considerably diminished in number ( Discocotyle ), 

 or can even be completely absent ( Diplozoon) . In addition to the edge (hooks 

 nobis), the larvae are equipped with 1-2 pairs of middle hooks and often 

 with one pair of clamps of the same structure as in the adult animals. For 

 the most part the larvae have one double eye, more seldom there are 2 

 pairs of them; often the eyes are completely absent. The attaching apparatus 

 among the adults consists of metamorphosed suckers having valve structures 



481 



