REPTILIAN TAPEWORMS. 29 



proglottid. The cirrus-sac is longer than broad, but not of a very 

 regular oval ; its walls are thin but muscular in structure, the 

 number of fibres in a longitudinal section not appearing to be 

 more than one or two. Within the cirrus-sac lies the cirrvis, 

 which widens out considerably in its last section — i. e., that lying 

 immediately after the external aperture ; the cirrus lies in many 

 <ioiis and is throughout of considerable calibre. In structure it 

 differs from the cirrus of many other tapeworms (see text-fig. 8) 

 by the very thick layer of circular muscular fibres which sur- 

 rounds it. The muscles are increased at the broad terminal 

 portion of the cirrus. Outside the muscles is a layer of pear- 

 shaped glandular cells which deck the whole of the cirrus. The 

 same arrangement, or something very like it, apparently exists 

 in Ichthyotcenia nattereri according to the figure and description 

 by Schwarz *. In that species, however, the glandular layer is 

 neither so thick nor so widely distributed as in the present. 



I have observed in several proglottids the complete protrusion 

 of the cirrus, which is everted in the usual way and thus is broader 

 at the base than at the tip, 



I have found no protrusion of the cirrus-sac itself such as has 

 been referred to by Schwarz. The cirrus when fully everted is 

 not half the width of the proglottid. There is thus a difference 

 from /. nattereri^ in which species (very like the present in many 

 respects) Schwarz asserts that the protruded organ equals in 

 length the whole diameter of the segment. Moreover, he figures 

 the cirrus as very much more closely coiled within the cirrus-sac 

 and therefore longer than I have found to be the case with my 

 new species. I have not found any spines upon the cirrus. As 

 in many species of Ichthyotcenia, the cirrus opens sometimes 

 in front of and sometimes behind the vagina. The cloaca 

 genitalis into which both open is of some depth. 



At its outer end (see text-fig. 8 B) the vagina is quite as wide 

 as the somewhat dilated end of the cirrus; but it very soon 

 narrows into a tube of less calibre. The wide distal region is 

 fully as muscular as the cirrus and it is furnished in addition 

 with a strong circular muscular sphincter. Outside of this is a 

 layer of glandular cells, which forms with those belonging to 

 the cirrus, and which have been already described, a common 

 layer surrounding the two tubes in one circle. In this region the 

 vagina is not ciliated. A little further back the vagina has its 

 own separate coat of glandular cells as has the cirrus. Later 

 on the vagina becomes narrower and is ciliated internally. It 

 bends back in the usual position and is coiled posteriorly in 

 the region of the ovary. The straight part of the vagina which 

 passes backwards lies dorsally to the uterus, but not quite in the 

 naedian line. 



The ovary extends on either side up to the laterally placed 

 vitelline strips. I could not find any signs of a shell-gland which 



* IjOC. cit. Taf. ii. fia-. 5. 



