^RT. 7 CESTODE PARASITES OF BIEDS LINTON O 



cation of proglottides further than is shown by the successive sets 

 of reproductive organs. Rudiments of these may be seen about 3.5 

 rnm. from the anterior end; ova make their appearance 10 mm. or 

 less from the anterior end. At the distance of about 20 mm. from 

 the anterior end the sets of reproductive organs are about 0.15 mm. 

 apart. Toward the posterior end four sets of reproductive organs 

 occupied a length of strobile of only 0.63 mm.; near the posterior 

 end three sets, now represented by egg-masses, took up 0.92 mm. 

 of length. In another strobile three egg clusters occupied a length 

 of 2.10 mm. 



The anatomy, as revealed by several series of sections, agrees 

 with that given by various authors. A diagrammatic representation 

 of the genitalia reconstructed from a series of transverse sections is 

 given in Figure 4. 



In a transverse section made 1 mm. from the anterior end the 

 thickness of the cuticle is 0.02 mm., subcuticula 0.14, longitudinal 

 muscle layer 0.11, circular muscle layer 0.11, medulla 0.14. The 

 subcuticula consists of a dense layer of radial fibers with numerous 

 fine longitudinal fibers interspersed. At the edge of the subcuticula, 

 next the layer of longitudinal muscles, there is a layer of nuclei 

 deeply stained, which represents the rudiments of the vitellaria. The 

 longitudinal fibers of the cuticula are in clusters and appear to be 

 very small fascicles of fine longitudinal muscles. The bundles of 

 longitudinal muscles in transverse section are much elongated radi- 

 ally, and the individual fibers are closely crowded and numerous. 

 The layer of circular muscles is here strongly developed, beingi of 

 about the same thickness as the longitudinal layer. The medulla is 

 narrow, a little less than one-sixth the thickness of the strobile at 

 this point. The structure of the adult strobile differs from the fore- 

 going principally in the space occupied by the vitellaria, which lies 

 between the subcuticula and the layer of longitudinal muscles. Thus 

 in a transverse section 3.36 by 0.70, at a point where the thickness 

 of the strobile was about 0.60, the thickness of the cuticle was 0.009, 

 the subcuticula 0.07, the vitelline layer 0.07, the longitudinal muscle 

 layer 0.08, the circular muscle layer 0.03, and the thickness of the 

 medulla 0.10. The longer diameter of the testes is dorso- ventral and 

 is about equal to the thickness of the medulla. At this level the fibers 

 of both longitudinal and circular muscles are coarser than they are 

 near the anterior end of the strobile. The medulla is crossed by 

 numerous rather strong dorso-ventral fibers which can be traced 

 across the circular muscles and between the bundles of the longi- 

 tudinal layer. 



The ova varied in greater diameter from 0.057 to 0.069, and in 

 lesser diameter from 0.036 to 0.042; average of fourteen 0.061 by 

 0.039. 



