2IO W1NTERTON C. CURTIS. 



number in the longest specimens it appears that there may be 

 formed upwards of 400. 



In the case of the anterior proglottids the total number formed 

 can be ascertained with more certainty for it is only necessary 

 to count them in specimens where the zone is just being obliter- 

 ated. Such counts show that there may be as many as 604 

 proglottids formed in the anterior region. I have found a few 

 cases in which the zone seemed about to be obliterated when 

 there were only 3035 anterior segments, but in the great ma- 

 jority of such cases their number runs well up toward 60 and 

 I think 50 -f would be a fair statement of the average number. 



The transition of the posterior segments into the unsegmented 

 zone is always gradual, as will be seen in Figs. 13, PI. V., 23 

 and 25, b, PI. VII. On the other hand the anterior segments 

 may show a gradual transition into the zone (Fig. 13, PI. V.) or 

 the transition may be more or less abrupt (Figs. 23 and 25, b, 

 PI. VII.) The condition shown by Fig. 25, b, is the more com- 

 mon one for the anterior proglottids while that shown in Fig. 13, 

 PI. V., is typical for the transition of the posterior ones into the 

 zone. 



When the zone is finally obliterated it is no longer possible to 

 tell where it was located for the proglottids of the anterior end, 

 with their four-pointed lappets, gradually change into the straight 

 transverse lines which separate the many immature proglottids in 

 the middle region of the chain. The adult condition thus ob- 

 tained is represented by Figs. 14, aii, in which typical regions 

 of the body have been drawn and the length of the chain between 

 such regions shown by straight lines. The peculiar anterior pro- 

 glottids (Fig. 14, a) still show their characteristic outlines as far 

 back as the I loth proglottid from the scolex (Fig. 14, <:) from 

 which we may conclude either that the specimen figured had 

 formed a greater number of anterior proglottids than I estimated 

 as the average, or that some of the proglottids formed behind 

 the non-segmented zone have assumed the character of immature 

 anterior proglottids. From the condition shown at the I loth 

 segment of Fig. 14, c, we reach after a distance represented by 

 the line d a region of very close-set immature proglottids which 

 are separated by straight transverse lines without any sculpturing 



