144 CHILD. 



Part I. (Child, 'oo) was devoted to the description of cases of 

 this kind and the Figs. 223 show a large variety. Bearing in 

 mind the method of formation of each proglottid from the two 

 distinct lateral groups of nuclei in the central parenchyma, /. e., 

 from two separate right and left halves which later become 

 united, it is not difficult to understand how the conditions repre- 

 sented in Figs. 2-23 have arisen. 



The cases which differ least from the normal form are those in 

 which the furrows between two proglottids are interrupted at some 

 point or points (c. g., Figs. 11, 12, 13, 15, 16, etc., Part I.). In 

 these cases the proglottids arose in nearly the normal manner. 

 The growth of the two, however, has not been sufficiently dis- 

 tinctly localized to cause the appearance of complete furrows. 

 The various degrees of fusion are indicated in each case by the 

 extent and distinctness of the furrows and the condition of the 

 genital organs. The furrows on the two surfaces of the body 

 may or may not correspond in cases of this kind, /. e., the growth 

 may be more distinctly localized on one surface than on the other 

 or may be alike on both. 



In all of the cases just noted, right and left halves of each pro- 

 glottid are present, and each must have been represented origi- 

 nally by a more or less distinct group of nuclei. In other cases 

 only the right or left half or smaller fractional portion of the pro- 

 glottid appears, the remainder not being represented. Such 

 variations are clearly the consequence of the formation and 

 growth of a proglottidal anlage on one side of the neck-region only, 

 no corresponding group appearing on the opposite side (Fig. 18, 

 Pt. I.), or else there are two small groups on one side correspond- 

 ing to one larger group on the other (Fig. 9, Pt. I.). Whether 

 the partial proglottid is entirely distinct (Fig. 18, Pt. I.) or united 

 with a whole proglottid (Fig. 9, Pt. I.), depends probably upon 

 the time of its formation. If two anlagen are found on one side 

 of the body at the same time that one appears on the opposite 

 side, the two of the one side are likely to become connected with 

 the one of the other, thus producing what appears to be a partial 

 division of the proglottid in the transverse plane (e. g., Figs. 9^ 

 10, etc., Pt. I.). If, however, an anlage appears on one side with- 

 out any corresponding to it on the opposite side, a partial pro- 



