ANATOMY OF MONOPYLIDIUM PASSERINUM, FUHR. 407 



those shown in Krabbe's figures, but otherwise the resem- 

 blance is close. 



Strobila.— The scolex is followed by an unsegmented 

 neck of nearly 0*4 mm. long, the breadth gradually increas- 

 ing from 0*11 to 0*13 mm. The segments are at first very 

 narrow and though transverse septa are present, the 

 marginal limits are not well marked. Then there follows 

 a comparatively rapid increase in length and a very gradual 

 increase in breadth, the serrated margins now becoming 

 evident. In the greater part of the strobila the proglottids 

 are trapezoid, those with well-developed genitalia being 

 about 0*4 mm., increasing to 0*64 mm. in length with a 

 breadth of about 0*5 mm. in the posterior region. Fully 

 ripe segments were not seen, but some which contained 

 developing oncospheres, were about 0*4 mm. broad by 1*2 

 mm. long. Fuhrmann mentioned that ripe segments may 

 reach 0*45 mm. in breadth by 1*6 mm. in length. There is 

 thus a considerable lengthening and a slight narrowing 

 as ripening progresses. The overlapping of segments is 

 slight and altogether disappears later. Occasionally the 

 trapezoid form may be replaced by a more rectangular 

 shape even in proglottids with well developed genitalia. 



Sex openings : — These alternate irregularly. There 

 may be a slight genital papilla present. The cloaca is 

 situated on the edge near the junction of the anterior 

 fourth, and the posterior three-fourths. It is very small 

 and shallow, being only 0*025 mm. in depth. 



Muscles, etc.— The cuticle is fairly thick. Below it is a 

 very well marked subcuticular layer. The muscles are 

 rather poorly developed. The longitudinal bundles are in 

 thin strands arranged in two concentric series, the greater 

 number being situated in the outer one. Transverse fibres 

 are very weak, whilst the dorso-ventral fibres were not 

 recognised. 



