No. 5.] THE CESTODE MONIEZIA EX PANS A. 237 



comparison with the pores at the right. This approximation of 

 the pores is evidently due to the incomplete separation of the 

 two segments, which, though separated dorsally, are united 

 ventrally. Thus, while the existence of the pores seems to be 

 determined by the relations upon the dorsal surface, their posi- 

 tion may be affected in some slight degree by the relations on the 

 ventral surface. 



Figure 20. 



The series of abnormalities shown here is rather complex and 

 may be considered most conveniently segment by segment. The 

 ventral surface is uppermost. 



The segment a is partially divided on the left side by a furrow 

 which extends from a point on the ventral surface very near the 

 edge around the edge to the dorsal surface, and for a short dis- 

 tance on the dorsal surface, where it ends free. The degree of 

 separation is sufficient to cause the appearance of two distinct 

 and complete sets of genital organs. At the edge the division 

 is complete, and accordingly the pores lie in practically their 

 normal positions on each side of it. The division, as indicated 

 by the furrow, extends only a short distance on either surface, 

 but farther on the dorsal than on the ventral surface, and the 

 arrangement of the ducts, ovaries, etc., is in accord with these 

 relations. The two ovaries, etc., are quite closely approxi- 

 mated, but the ducts diverge, thus indicating that the division 

 becomes more complete with the approach of the edge. This 

 case, like Fig. 10, b and c, illustrates, though in a less degree, the 

 apparent existence of a certain degree of separation in regions 

 where the furrows do not appear. Thus there is no furrow on 

 either side immediately between the ovaries, yet two sets appear. 

 That the division is more complete dorsally than ventrally is 

 shown by the fact that the dorsal furrow is longer than the 

 ventral, and the position of the genital organs accords with this 

 fact as shown above. At the right a shows no trace of division, 

 and a single normal set of organs is present. 



The segments b and c are best considered together. At the 

 right, before reaching the edge, both the dorsal and ventral fur- 

 rows separating b and c bend anteriorly and become very slight, 



