88 Transactions of the Royal Canadian Institute. [vol. x. 



fibrils (Fig. loc) points to a specialization among many sets of fibres in 

 the direction of the complete loss of the nuclei, the presence of which is 

 made the basis of a classification of the muscles of cestodes by Braun 

 ('94-'oo). 



The coronal or transverse series of muscles is arranged 

 as two thin sheets of fibres lying immediately within the longitudinal 

 muscles of the parenchyma, thus assisting the latter in forming the 

 boundary between the medullary and cortical parenchyma. In trans- 

 verse sections the fibres of these two layers diverge laterally so that the 

 innermost cross or interdigitate before they become attached to the 

 cuticle. In the posterior end of the anterior proglottis each layer sends 

 many fibres to the auricular appendages of the same surface of the worm 

 (Fig- 35). which curve slightly posteriorly to form part of the radiating 

 fibres of the latter. While the dorsal and ventral bands are continuous 

 from joint to joint throughout the anterior portion of the strobila, there 

 is a decided augmentation in the number of fibres in the posterior portion 

 of the proglottis opposite the auricles into which they pass. Farther 

 back they diminish in number with the reduction in the size of the 

 appendages, relatively more quickly in the forward part of the joint, 

 until in the unsegmented hinder end only a few straggling fibres appear, 

 in the interproglottidal regions, between the testes and the vitelline 

 glands. 



In addition to these another series of transverse fibres, more circularly 

 arranged, appears in the anterior end of the strobila, especially well- 

 developed in the first three or four joints. They are divided into eight 

 groups, two for each surface, and are situated immediately beneath the 

 subcuticula. Each group consists of parallel fibres arising along 

 the whole of the edge of the proglottis ahead of the appendages and 

 passing obliquely and posteriorly into the opposite appendage of the same 

 surface. Thus there is a decussation in the mid-line, giving rise to rather 

 complicated appearances in cross-sections. The two pairs of lateral groups 

 which can be best seen in sagittal sections, are related to each other in 

 exactly the same way; they are, however, not quite so extensive, as may be 

 expected from the ligulate habit of the worm, the dorso-ventral diameter 

 even in these foremost joints being considerably less than the transverse. 

 Beginning at the base of the appendages, that is, the anterior edge of the 

 ring (vide supra) to which they are attached, small groups of these 

 coronal muscles are cut ofi' from the inner groups at the ends of the 

 diagonal diameters of the joint by the external longitudinal fibres of the 

 parenchyma to pass back into the appendages and supply them with a 

 circular musculature (Fig. 35). All of the oblique fibres gradually dis- 

 appear with the auricles posteriorly, so that they are developed evidently 



