832 DR. F. E. BEDDARD ON A 



I selected for investigation, by means of transverse sections, 

 the most adult-looking of the young budded-ofl' worms, in which, 

 moreover, segmentation was obvious. I have already referred to 

 this individual in my account of the budding process and need 

 not redescribe its external characters here. The wider end 

 attached to the body of the parent forms a bladder with rather 

 thick walls. This I take, therefore, to be the posterior end of 

 the young worm. The opposite end is very much thinner (as is, 

 of course, usual among tapeworms) and represents the scolex end 

 of the animal. I could observe no trace of hooks anywhere on 

 this scolex, nor suckers of any kind. This, however, is not sur- 

 prising in view of what I have already described in considering 

 the conditions observable in the parent stock. At about the 

 middle of the worm a transverse section shows the appearances 

 represented in text-fig. 116. The cortical layer is thick — about 

 the same diameter, or in places rather more than the diameter, 

 of the medullary region. The medullary region is plainly marked 

 ofi" from the cortical by transverse muscular fibres of delicate 

 constitution. 



There are several parallel fibres in this layer, which is altogether 

 of some width, the individual fibres being widely separated. The 

 parenchyma of the medullary region is as usual, and contains 

 many nucleated cells, generally triangular in form, connected 

 with processes at the angles. These cells get to be particularly 

 numerous near the water vascular tubes, which will be referred 

 to later. There are also heaps of nuclei visible in some sections, 

 which I take to be the rudiments of the sexual organs. To one 

 side of the body the medullary region seems at first sight to be 

 invaded, as it were, by the cortical region, thus producing an 

 asymmetry in the transverse section, Avhich is quite apparent in 

 the accompanying text-figure. This asymmetry is associated with 

 the presence of a tubular organ (text-fig. 116, ;«), which will be 

 described in detail on a subsequent page. This occupies a good 

 deal of space, and round it are large bundles of stout muscular 

 fibres, quite similar to those which occur in the cortical layer. 

 It is very easy, however, to observe that the transverse layer of 

 muscles bounding the medullary parenchyma is continued on 

 either side of this differentiated mass of tissue and ends laterally 

 at a point asymmetrical with its ending on the other side of the 

 body. I therefore regard this region as belonging to the medullary 

 part of the body. The cortical region is distinguished from the 

 medullary (other than that section of the medullary region just 

 referred to) by the bundles of stout longitudinally running fibres. 

 These bundles form a layer immediately outside of the transverse 

 fibres ; but there are much smaller bundles and isolated longi- 

 tudinal fibres extending some way towards the exterior of the 

 body. 



In the medullary region lie the water vascular tubes and the 

 nervous system. All of these lie in the same straight line with 

 each other and with the tubular organ already referred to, and 



