IO2 CHILD. 



tail of the structure of the neck-region. The evidence on this 

 point is gathered and discussed in the following paragraphs, in 

 which the structure of the neck-region and the early proglottid is 

 examined in detail. 



Attention may once more be called to the fact that in the fig- 

 ures of sections the individual nuclei, except those of the subcu- 

 ticular layer, were drawn in with the camera, so that the arrange- 

 ment of the nuclei seen in the figures corresponds as closely as 

 possible to their arrangement in the actual section. As the 

 nuclei are distinct and not very numerous, the figures are prob- 

 ably free from serious inaccuracies in this respect. 



First of all in this connection, the two transverse sections, Figs. 

 42 and 43 (p. 96), require renewed consideration. These sec- 

 tions lie in the plane of the aggregation of nuclei and conse- 

 quently do not show them. Incidentally it may be mentioned, 

 however, that in following through a series of transverse sections 

 from the neck-region, the nuclei between the nephridial canals 

 and the longitudinal muscles are more abundant in some sections 

 than in others and that a certain, not very marked periodical re- 

 currence of the two conditions can be made out. The point of 

 immediate interest shown in Figs. 42 and 43 is the greater 

 abundance of nuclei in the lateral regions of the central paren- 

 chyma. In both figures the regions contain numerous nuclei 

 distributed with more or less uniformity, while the region be- 

 tween the two pairs of nephridial canals, though showing some 

 more or less distinct aggregations, contains in general fewer 

 nuclei. This point confirms the evidence afforded by the study 

 of whole mounts, viz., that the nuclei appear to be more abun- 

 dant in the lateral regions of the central parenchyma than else- 

 where when viewed from either surface. Of course in whole 

 mounts the distribution of nuclei in the central parenchyma is 

 more or less marked by the subcuticular peripheral nuclei. 



Longitudinal sections are necessary to show the groups of 

 nuclei. The frontal section, Fig. 44 (p. 97), is taken from near 

 the anterior end of the neck. It passes through the ventral 

 nephridial canals. The plane of the section is indicated by the 

 line 44 in Fig. 53. The nuclei of the central parenchyma are* 

 seen to be much more abundant lateral to the nephridial canals 



