24 DB. F. E. BEDDARB ON 



sometimes entirely free from testes. Tlie sperm-duct shows an 

 important difference from that of Ichthyotcenia vm'ia. Ahnost 

 immediately after leaving the cirrus-sac it becomes dilated into a 

 vesicula seminalis in a fashion not met with in the last described 

 species. Moreover, the coil of sperm-duct which ensues is con- 

 siderably less in extent than that of /. varia, and instead of 

 running out towards the middle of the segment is directed rather 

 obliquely and forwards. There is thus a greater angle formed 

 with the vagina. The structure of the cirrus-sac appears to me 

 to show no obvious differences from that of the Ichthyotcenia 

 which has just been described. The vas deferens is coiled within 

 it in a precisely similar fashion. As a rule the vagina, which lies 

 parallel with the cirrus and is here somewhat dilated, lies 

 posteriorly to that sac; but I found it in one instance to open in 

 front of the cirrus-sac. Ichthyotcenia gracilis thus differs in this 

 chai-acter also from Ichthyotcenia vcorici. In the neighbovirhood 

 of the ovary the vagina is a good deal coiled ; but my account of 

 the female organs of this species is very incomplete, since they 

 were not fully mature. The shell-gland Avas large and well 

 forward in development ; but I could not definitely recognise the 

 lateral vitelline strips. The uterus was in the condition of a 

 delicate thread commencing anteriorly and extending far back in 

 the middle line of the segment. 



I am therefore able to distinguish plainly three species of 

 Ichthyotcenia, occurring in the gvit of Varanus varius, which are 

 appai-ently graduated in size, and of which the smallest (to which 

 I do not venture to give a name for the present) is the only one 

 that bears any external likeness to the only species of Ichthyo- 

 tcenia (viz. /. tidswelli) as yet recorded from this particular 

 species of Varanus. I have, however, shown ample reasons for 

 regarding it as different. There can also be no question as to the 

 m.arked distinctness of /. varia and /. tidswelli quite apart from 

 size, and here there appears to be too great a discrepancy to allow 

 of specific identity. /. tidsivelli differs from my species by its 

 total lack of calcareous corpuscles, by the alternating relative 

 position of cirrus-sac and vagina, by the disappearance of the 

 uterus and the lodgment of the ripe ova in the parenchyma *, by 

 the freedom from testes of the middle region of the proglottid, 

 and by the strong muscular layers of longitudinal fibres lying 

 within the subcuticular layers of cells. 



"With my Ichthyotcenia gracilis Johnston's /. tidsioelli agrees 

 more closely; yet they are, as I think, different. In the first 

 place, /. grcccilis cannot possibly be described as " like a piece of 

 fine white thread," a description applied by Johnston to 

 /. tidsivelli. I can find neither in /. gi-acilis nor in /. varia the 

 strong muscular layer figured by Johnston, and also in other 

 species by Schwarz. Finally, the existence of what may be 



* The author of the paper upon I. tidswelli is not, however, able to insist 

 absol-ately upon this. 



