594 DR. F. E. BEDUAllD ON 



that of the medullary layer. This is particularly marked in the 

 anterior segments, where the reproductive organs are only just 

 beginning to appear. The longiiudincd muscle-layer presents 

 definite characters in the arrangement of its fibres, as is general 

 among Cestodes. It is not usual to find accurate figures of the 

 course of these fibres, which are constantly of systematic im- 

 portance. I therefore ittempt to reproduce here such accurate 

 .drawings. 



At the base of the rostellum the longitudinal muscles lie in a 

 continuous circular layer, in which form they are implanted upon 

 the rostellum. A little further back, at the level of the suckers, 

 the layer of muscles is markedly divided up into separate bundles 

 which are of different sizes. There are 12 or 13 of these 

 separate bundles which are more or less completely sepai-ated. 

 In the Heck, which immediately follows upon the scolex, the 

 bundles cease to exist as separate structures except at the two 

 sides opposite to the water-vascular tubes. The unsegmented or 

 neck region in this worm is very short and, as in the other 

 examples ascribed to the species Tcmia struthionis vel T. struthio- 

 cameli, it may fairly be remarked that a neck can hardly be said 

 to be present. Further back— but still in the anterior region 

 of the body, where the gonads and their ducts are still only 

 recognizable as a mass of condensed nuclei — the longitudinal 

 muscular layer has more or less acquired its definitive arrange- 

 ment. It is here (text- fig. 2) divisible into two quite distinct 

 sheets. That nearest to the medulla consists of a row of 

 bundles each consisting of a good number of individual fibres 

 which are packed close together and separated by vertical fibi'es 

 forming a dividing palisade. Above this is a very distinct space 

 dividing the lower layer from the upper. This space is formed 

 of ground-tissue, and thei'e is no trace therein that I could 

 discover of transverse muscle-fibres. On the outer side of this 

 space is a layer of smaller bundles, i. e. each bundle consisting 

 of comparatively few fibres, and above this again, without any 

 marked interval, a certain'number of single muscle-fibres, which 

 complex reaches some way towards the subcuticular layer. In- 

 side the whole longitudinal layer of muscles is a thin layer of 

 transverse fibres separating these in the usual way from the 

 medulla. Further back in the body the same arrangement 

 exists, but it is not so clear cut as anteriorly. That is to say, 

 the two layers of the longitudinal sheet are quite recognizable, 

 but they are. not so markedly divided from each other. This is 

 shown in text-fig. ,3. 



Besides the sheets of muscle mentioned so far, the worm has, 

 like most other Cestodes, a dorso-ventral system. I have already 

 spoken of dorso-ventral fibres running between the bundles of 

 the longitudinal coat. In addition to these the medulla is 

 traversed by single fibres Avhich cross it at right angles to its 

 long diameter, and are numerous, dividing the medulla into quite 

 narrow segments when seen in transverse sections. 



