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



unsegmented portion of the strobila the question of the length is a very 

 difficult one to decide upon. Perhaps only the longer kind is to be found 

 here, since, as above stated, no indication of proglottidation, apart from 

 the separate sets of reproductive organs, was detected. There is thus 

 a certain amount of interruption in the course of the longitudinal muscles 

 corresponding to the division into proglottides as pointed out early by 

 Leuckart for Taenia saginata Goeze (Braun 'oo). Furthermore, 

 there is a slight contraction of the whole cylinder of fibres as the inter- 

 proglottidal space is neared (Fig. 37), which is not to be seen after the 

 auricles have disappeared. 



The outer longitudinal muscles appear only in the anterior proglot- 

 tides and scolex in connection with the appendages, for the movement of 

 which they are obviously developed. In the anterior half of the pro- 

 glottis they lie very close to the longitudinal cuticular muscles from 

 which they can be distinguished only by their slightly larger size. As 

 they pass the slight indentation which in coronal series marks the anterior 

 end of the appendage, they are joined by other fibres attached to the 

 anterior portion of the outer wall of the latter, so that when they are 

 Converging towards the center to pass into the next porglottis, they form 

 a ring of fibres more prominent in cross-section than those of the inner 

 longitudinal group (Fig. 35). Throughout their course they are also 

 more prominent opposite the auricles than at the ends of the dorso- 

 ventral and transverse diameters. Just ahead of the sinus or pocket 

 behind the auricle a few fibres are cut off from the main body to pass 

 about half way along the inside of the appendage. The latter is further 

 supplied with very many fibres belonging to the same group (Luehe '97) 

 which pass between its outer and inner walls to the very tip (Fig. 37) 

 and, by their contraction, obviously serve to protract the edge of the auri- 

 cle and thus to allow the minute spines to catch in the mucous lining of 

 the host's intestine. As the appendages diminish in size this series of 

 muscles gradually becomes restricted to the hinder end of the proglottis 

 and eventually disappears with the former. 



Thus, so far as proglottidation in relation to the arrangement of the 

 external longitudinal fibres is concerned, this species resembles Ligula 

 uniserialis Rud. and strongly substantiates Luehe's generalization 

 that: "wenn die Proglottiden eines Cestoden, wie dies in der Regel 

 wenigstens bei jugendlichen Proglottiden der Fall ist, am Hinterende 

 einen grosseren Querschnitt besitzen, als am Vorderende, dergestalt, 

 dass die einzelne Proglottis mit einem seitlich abgeflachten Kegel ver- 

 glichen werden kann und ein Langsschnitt durch mehrere Proglottiden 

 eine der Schneide einer Sage ahnliche oberflachliche Begrenzung besitzt, 

 so sind stets auch Muskelfasern vorhanden, welche an der Aussenflache 



