HELMIN THOLO QIC A L NO TES.— JOHNSTON. 



187 



latter disappear just behind the level of the base of the suckers. Each sucker 

 has a diameter of about -35 to 4 mm., and possesses a deep concavity. An 

 apical sucker is absent, though a slight terminal depression can be seen on the 

 seolex (tig. 2), and into it are inserted a few weak muscle fibres. The cuticle of 

 the seolex is smooth and thin, though somewhat thicker on the suckers than on the 

 rest of the seolex. 



The neck region is about -7 mm. in its narroAvest part, the strobila 

 gradually widening, until mature segments reach a breadth of about 14 mm. 

 and a length of about 2 mm. The proglottids are rectangular, being at first 

 broader than long but later become squarish and ultimately longer than broad. 

 Segmentation is not readily visible, the parasite having the appearance of a 

 thin, narrow piece of tape. Genital pores alternate irregularly and there is no 

 definite genital papilla. 



The cuticle of the strobila is very thin and practically smooth. The 

 subcuticula possesses very closelj^ set and well-developed longitudinal muscle 



Fig. 3. — Transverse section of the anterior end of the seolex, showing subcuticular longi- 

 tudinal muscles (s.c.l.m.), also the musculature of the parenchyma and suckers. 



Fig. 4. — Section through seolex in vicinity of nerve-ring (n.r.), showing diagonal muscle 

 fibres {d.tn.f.). 



bundles arranged in a series next to the cuticle and occupying a zone of about 

 •04 mm. in width (figs. 9, 17). The cortex contains numerous calcareous 

 corpuscles, varying in size from -15 to -08 mm. in long diameter by -08 to -04 mm. 

 in short diameter, and averaging about -06 by -04 mm. (Fig. 9.) 



Mnscular System.- — The main musculature lies inwardly from the zone 

 containing the calcareous bodies. The longitudinal muscles are well developed 

 especially in the seolex and neck, while the transverse fibres are A^ery weak and 

 often not recognisable, nor are the dorsoventral fibres well marked. 



The longitudinal musculature of the segments forms a well-defined ring 

 consisting of numerous small bundles arranged more or less in a single series, 

 though not infrequently isolated bundles lie inwardly from this ring (text-figs, 

 13, 17), and in places the arrangement is such that there appears to be an inner 

 and an outer series (fig. 17). 



A powerful sphincter surrounds the common genital atrium (figs. 11, 14). 



