NEW MAMMALTAX TAPEWORMS. 1011 



duction generally. I found, in fact, that the uterns Avas quite 

 recognisable in the first segment which had a fully developed 

 cirrus pouch, and that segment was one of the earliest to have 

 attained an appi'eciable length and lay hardly a millimetre 

 behind the scolex. In this segment the uterus showed (in a 

 longitudinal horizontal section through the anterior region of the 

 body) a rounded form stretched in the direction of the transverse 

 section of the body and thus rather oval in outline, and it 

 occupied precisely the median region of the proglottid. In this 

 particular uterus I found no ova. A segment or two further 

 back the uterus is already larger, but it still has the form of a 

 more or less oval sac, extending in these segments towards the 

 pore-side and having thus become eccentric in position. The 

 eccentricity, however, is not very strongly marked. In these 

 segments the uteri were full of ova. 



The uterus in these segments lay near to the posterior boundary 

 of the proglottid and w^as transversely elongated in form ; it 

 was distinctly posterior to the strong muscular cirrus sac. The 

 uterus possessed a distinct epithelial wall that was of sufficient 

 thickness to show itself in all my sections {cf. text-fig. 210, p. 1007). 

 Later, the epithelial wall is not obvious, but the cavity has plain 

 bovmdaiies and can be recognised as a definite cavity and not 

 merely a system of irregular lacunfe. 



In the posterior ripe proglottids the uterus undergoes some 

 changes which are not altogether easy to follow and to correlate. 

 "When the elongated, fully ripe proglottids are examined mounted 

 in glycerine, the eggs are seen to be arranged throughout them 

 in a way which differs slightly in different proglottids but 

 is as a rule at any rate on the same plan. The eggs occur in 

 clusters and strings which give the appearance of a retiform 

 uterus. In this, at times, a median string of eggs giving off 

 lateral branches may be recognised. And though these lateral 

 branches join here and there and thus make a netwoi-k, the 

 general appearance given in such segments is that of the uterus 

 of Tceiiia, Avhich is characterised by a median stem and lateral 

 branches. Very commonly the ova are moie thickly clustered 

 together in the posterior region of each segment. There is, I 

 think, little doubt that if the worm were examined only in this 

 way, the uterus wovild be pronounced to be reticular. A study 

 of sections, however, leads to a rather different interpretation of 

 the arrangements visible in solid preparations. In some trans- 

 verse sections, such as that illustrated in text-fig. 212, the whole of 

 the inteiior of the proglottid is occupied by the uterus and the 

 contained masses of developing eggs. These appear to lie in a 

 large undivided cavity, which I take to be the uterus. This 

 region corresponds to the posterior part of the segment, where as 

 already mentioned the eggs tend to become massed. 



In other sections through the same proglottid as that which 

 has just been referred to, the conditions observable were different. 

 There are, as is shown in the accompanying figure, eggs and 



