Cestode ike. from Spitsbergen. 



423 



in de|)tli nearly a quarter of the total dorso-ventral diameter 

 of the worm. The Ionj,Mtu(linal musculature is well- 

 develo[)ed, consisting of an inner layer (fig. 2, i.l.in.) of 

 larger, ;md an outer layer (fig, 2, o.l.vi.) of smaller, bundles 

 of fihres. Of the former there are about twenty bundles 

 dorsally and a similar number ventrally. They lie imme- 

 diately outside the very scanty layer of transverse fibres 

 (fig. 2, /.m.), which forms the boundary between the cor- 

 tical and medullary parenchyme. At the level of this 

 transverse layer, on the ventral side, lie the two large 

 ventral longitudinal excretory canals (tigs. 2, 3, e.). Dorsal 



o./.m. 



Am. 



Anophryocephalus anopkri/s. Transverse section tbrough 

 a mature segment. 

 C.S., cirrus-sac ; e., e., excretory vessels ; f/.a., genital atrium ; i.l.m., 

 inner layer of longitudinal muscles ; n., n., longitudinal nerves ; 

 o.l.m., outer layer of longitudinal muscles; ov., ovary; t., t., 

 testes ; t.m., transverse muscles ; tit., uterus ; vag., vagina ; 

 vit., yolk-gland. 



longitudinal canals and transverse connecting vessels between 

 the ventral canals appear to be entirely absent. 



The genital pores arc all on the right side. The genital 

 duets pass dorsally to the excretory canal and ventrally to 

 the longitudinal nerve of that side. The external pore leads 

 by a narrow canal into a ratlier small genital atrium 

 (fig. 2, g.a.), corresponding to that of Tetrabothrius, into 

 which the cirrus-sac and vagina open separately, the latter 

 ventrally to the former. Immediately below the opening of 

 the vagina the wall of the atrium forms a small, rounded, 



