188 DE. F. E. BEDDARD ON THE 



appears to me of sufficient weight to imply generic, if not specific 

 identity. 



I have now to direct attention to a few additional facts in the 

 anatomy of this species. With reference to the water- vascular 

 system, I confirm my former statements as to the numerous 

 folds which project now from this .side and now from the other 

 into the lumen of the large ventral tube. It is to be noted, 

 however, that when the segments are more stretched — as they 

 are in individuals which I have just finished examining — the 

 depth of these folds is diminished. Nevertheless, they are still 

 present, and I have never seen the tube to be bounded for any 

 considerable length by straight parallel lines such as are usually 

 seen in most Cestode worms. I have omitted to mention in my 

 earlier paper, that at the boundary line of each proglottid the 

 tube is much dilated ; it is just at this point that the transverse 

 tube might be expected to arise, were it present, at any rate 

 judging from the conditions figured by Braun (after Zschokke in 

 Bronn's " Thierreichs " *), where the dilatation appears to that 

 author to be the physiological equivalent of a valve. I have 

 ascertained that there is also a valve present in this situation in 

 Dasyurotcenia robusta. I have mentioned in the paper referred 

 to that a closed septum occludes the lumen at these points. 

 This statement is partly true, for such a septum can readily be 

 seen. But when followed out through its whole superficies the 

 diaphragm is seen to be free in the middle region, and thus to 

 form a flapping valve which arises from the internal side of the 

 tube (as usual but not universal), and to rest against the opposite 

 side in such a fashion that it entirely occludes the lumen of the 

 water- vascular tube in this area. In parts it is, ns already said, 

 a veritable fixed diaphragm. In view of the existence of the 

 swelling upon the course of the ventral water- vascular tube 

 and the presence of a valve, I looked very carefully to ascertain 

 whether a transverse vessel might not be found ; but I have quite 

 failed to make out such a tube, although there is in the proper 

 position a slight process of the tube directed inwards. 



In connection with the above remarks upon the water-vascular 

 system of this Cestode, it should be mentioned that the recent 

 specimens examined by myself show that the ripe proglottids are 

 longer relatively to their breadth than I originally described. 

 They attain to a length rather greater than their breadth. 



The uterus in the more fully ripe proglottids has not the simple 

 form which I found and described in the first specimens of this 

 worm which I investigated and reported upon. As the proglottids 

 grow in length the uterus grows into outgrowths and completely 

 but irregularly fills the available room in the proglottid. It does 

 not appear to form a network, but merely an irregularly shaped 

 sac. The generic definition of Dasyurotmnia must therefore be 

 slightly amended. The mature uterus contained mature ova, 



* Bd. iv. Abth. I.B. taf. li. fig. 6. 



