No. 5.] THE CESTODE MONIEZIA EXPANSA. 21 7 



incomplete separation of two proglotticls or parts of proglottids, 

 and the "partial furrow' is the furrow separating a partial 

 proglottid from others ; it may end free or may join another 

 furrow. In many cases the furrows gradually become less and 

 less distinctly marked and are said to become shallow as their 

 depth is less than that of the normal furrow. 



In anticipation of the summary it seems advisable to mention 

 briefly some of the more important facts which may be gathered 

 from the study of these abnormalities. 



Taking as the basis for comparison the normal proglottid, 

 numerous variations from this type are found. The segment 

 may be longer or shorter than the normal, or may vary in length 

 in different parts. The furrows bounding the segments may 

 end at any point, leaving two or more segments partially united, 

 or they may bend so as to run longitudinally. The furrows are 

 evidently the expression of internal conditions, and where abnor- 

 malities in the furrows occur, the internal organs very often 

 show abnormalities in arrangement and position which are very 

 closely correlated with the position and development of the 

 furrows. In brief, the position, development, and arrangement 

 of the sexual organs are very closely correlated with the form 

 and size of the proglottid. The organs which lie nearer the 

 ventral side are affected chiefly by the form relations on that 

 side, and those which lie nearer the dorsal side by the conditions 

 there. This appears very clearly in many cases where the form 

 relations on the two sides of the body do not correspond. Some 

 cases appear to indicate that a certain degree of distinctness or 

 separation, an "internal division," may exist without the appear- 

 ance of distinct furrows. Between this condition and the normal, 

 various degrees of division are indicated by shallower or deeper 

 furrows. The various portions of the sexual organs, e.g., the 

 proximal and distal portions of the ducts, develop independently 

 of each other in situ, and become connected secondarily, or in 

 many cases remain separated. Abnormalities of the furrows are 

 apparently due to the internal conditions in the growing regions. 

 The abnormalities of the internal organs must be regarded as 

 adaptations to the abnormal relations of form, size, etc., which 

 already exist in the segment concerned. 



