TYPES OF SPECIES OF CKSTODA — KREFFT. 21 



material the proglottids are much h j ss variable, and resemble 

 those shown in PI. Hi., fig. 3, except that the margins are more 

 definitely seriate. 



No subcuticular structures are recognisable on account of the 

 maceration which the specimens have undergone. Calcareous 

 corpuscles are very abundant in the cortex. They are rounded 

 or elliptical, varying in size from 0-001 by 00035 to 001 18 mm. 

 by 0-0095. The outer longitudinal muscle bundles are well 

 developed and are distributed throughout the outer portion of 

 the cortex. The inner series consists of a well marked ring of 

 relatively large and numerous bundles arranged in a double row, 

 those in the inner row being larger and less numerous than 

 those in the outer row. Transverse fibres were recognised only 

 in a few sections. 



The excretory system consists of a wide ventral and a narrow 

 dorsal vessel, the latter being situated just above the former. 

 The genital ducts pass above both of them. Transverse vessels 

 were not detected. The longitudinal nerve is located dorso- 

 lateral^ from the ventral vessel. 



Genitalia.— The genital pore is placed marginally and unilater- 

 ally at the junction of the anterior third with the posterior two- 

 thirds, there being no distinct papilla. The cloaca is moderately 

 long, its outer part being narrow while its inner end is relatively 

 wide. Into the latter there open the male and female ducts, the 

 latter being behind and below the former. 



Lying on the antero-dorsal part of the inner end of the cloaca 

 and opening into it there is a peculiar sac similar to that 

 described as being present in Hymenolepis sinuosa, Zeder. Its 

 walls are lined by cuticle and within this layer there are very 

 strongly developed muscles, most of which radiate from the sac, 

 while a few ring fibres are also present. The cuticle appears to 

 be minutely spinv but this appearance is clue to ends of the radial 

 muscles which give a "stippled" effect like that produced by 

 minute bristles. No spines were seen in sections of the sac. 

 The wide opening of this organ lies beside and above the male 

 opening, the sac itself which lies antero-dorsally to the outer end 

 of the cirrus sac, apparently acting in some way as an accessory 

 male organ. Two of the testes are situated on that side of the 

 ovary which is remote from the genital pore, the other vesicle 

 being on the opposite side. As will be seen from the figure 

 (PI. iii., fig. 3) two of the glands lie behind the female complex. 

 They are approximately equal in size, measuring about 113 by 

 008 mm. They disappear soon after reaching maturity, the 



