No. 6.] THE CESTODE MOXIKZIA EXl'AXSA. 285 



deferentia appear on either side. This rudimentary condition 

 of the male organs is doubtless due to the extreme shortness of 

 the proglottid. As on the left side of b in Fig. 38 the sperma- 

 tozoa have accumulated in some of the testes in the lateral 

 regions of the segment (/ /). In this case there is no exit on 

 either side of the spermatozoa, and the female ducts are incom- 

 plete and unconnected with the male ducts. Consequently the 

 segment is not functional. The spermatozoa cannot fertilize 

 the eggs of this or any other segment, and the eggs cannot be 

 fertilized by spermatozoa from this segment or from any other. 



The ventral furrow between b and c is distinctly abnormal, 

 especially at the left. A normal furrow does not cut into the 

 body vertically, but obliquely, and in such a manner that the 

 posterior edge of each proglottid seems to overlap the anterior 

 edge of the next succeeding. Over about two-thirds of its 

 course the ventral furrow between /; and c is normal in its 

 relations, though slightly irregular in its course. Over the 

 remaining third, however, - - the shaded portion at the left 

 marked /, - - it is a vertical furrow widely open to the surface, 

 and nearly twice as deep as the normal furrow by actual 

 measurement. It cuts almost halfway through the body and 

 thus separates b and c in this region much more completely 

 than they are separated elsewhere. This portion of the furrow 

 shows no inter-proglottidal glands, but they are present in the 

 more nearly normal portion. The ventral furrow anterior to c 

 is also abnormal at its left end. It is interrupted, one portion 

 turning anteriorly, and the other curving near the edge so as 

 nearly to enclose a small area. The dorsal furrow bounding c 

 is normal. 



In the segment c there are two normal sets of organs, the 

 one situated normally, and the other nearly so ; but in addition 

 to these organs a third set (c") appears situated to the right of r' 

 and consisting of a small ovary (<?), a vitellarium (vt], and a small, 

 empty seminal receptacle, which is closed. This case of trans- 

 verse duplication of organs is very similar to the one figured in 

 b in Fig. 38, and it is in the same region of the body, the two 

 being separated by some thirty segments only. This second 

 case does not afford any evidence as to the factors concerned 



