282 CHILD. [VOL. I. 



appear to be connected with any visible abnormalities in the 

 form of the segment or in the relations of its boundaries. The 

 two sets of organs taken together probably do not represent 

 more material than a single set of normal size. The left side 

 of the segment b is somewhat shorter than normal, but in Fig. 

 39, c, where a similar duplication occurs, the segment is of 

 very nearly normal length. The furrows bounding this region 

 of the segment seem to be normal, except that the distribution 

 of the inter-proglottidal glands in the dorsal furrow between 

 b and c is rather irregular. None appear in this furrow in the 

 middle region of the body, and only a few to the left of the mid- 

 dle. The furrow is normal in appearance, however, and the 

 other furrows seem to be normal in every respect. The con- 

 ditions found here may perhaps be due to the splitting of a 

 single genital mass in earlier stages, but if this is the case no 

 clue is afforded as to the cause of the splitting. If such a 

 division should occur, later growth would undoubtedly increase 

 the distance between the two portions. From a study of the 

 early stages of the genital organs and their method of origin I 

 am inclined, however, to believe that this extra set has arisen 

 in situ and without connection with the set b' . If this is the 

 case its appearance must be the result of certain internal con- 

 ditions, which present no other visible manifestation. 



This transverse duplication of organs constitutes a problem 

 entirely different from that of their multiplication longitudi- 

 nally. -Whether or not it is to be regarded as the result of a 

 kind of longitudinal division of the segment is doubtful. No 

 organs except the ovary and vitellarium are duplicated in this 

 case, i.e., the organs on the ventral side only. This is likewise 

 the case in Fig. 39. These two examples are the only ones of 

 this nature which I have found so far, but it is hoped that 

 additional material bearing upon this point may be discovered 

 and may serve to throw some light on the factors concerned in 

 the production of this peculiar abnormality. 



The regions c and d of the ventral side are separated by a 

 portion of the spiral furrow which runs almost longitudinally. 

 At the right it forms the posterior boundary of d, but turns 

 anteriorly and then continues as the anterior boundary of c at 



