ABNORMALITIES IN CESTODE MOXIEZIA. 



101 



increasing in width and each proglottid is growing longer as well. 

 Even at this stage the nuclei are seen to be more abundant in 

 the region of the nephridial canals. 



The Figs. 49-52 render it sufficiently evident, I think, that 

 each proglottid is simply an area of relatively rapid growth in the 

 parenchyma. The growth first becomes evident in the lateral 

 regions of the central parenchyma, /. e., between the nephridial 

 canals and the longitudinal muscles, where, as was noted above, 

 the nuclei are most abundant. It gradually extends from each 

 side across the middle region of the body, thus forming a zone, 

 which at first includes only the central parenchyma, but gradually 

 extends to the peripheral parenchyma. At last the growth be- 





FIG. 52. 



comes evident upon the surface, the regions in which it occurs 

 becoming convex as might be expected. At this stage then each 

 proglottid represents a transverse slice of the body which is in- 

 creasing in size more rapidly than the intervening regions, which 

 therefore become marked as furrows. The furrows are not to 

 be regarded as constrictions, but simply as marking the areas 

 where growth in the transverse direction is least rapid. 



The important points in the process are as follows : Each pro- 

 glottid arises as two distinct aggregations of nuclei, one on either 

 side of the body, which later extend toward the median line and 

 become continuous, and still later extend to the surface or at 

 least to the outer layer of the body. 



In Figs. 47 and 48, as noted above, there are traces of a trans- 

 verse arrangement of the nuclei in the lateral regions of the cen- 

 tral parenchyma into bands or groups. The question at once 

 i arises as to whether these groups represent the earliest stages 

 of the proglotticls, or whether they are connected with some de- 



