CuHTis.— Planar ia. 
PLATE 9. 
(The litj-ures on this plate were drawn from the live specimens increased 20 
diameters. They have been reduced three fourths in the reproduction.) 
Figs. 1, 2. A tail piece of P. rnaculata from the dorsal aspect a few hours 
after the normal fission. Figure 1 shows the anterior end drawn 
together as it is when the animal is at rest. Figure 2 shows the con¬ 
dition when the piece is moving actively about. The pigment flecks 
• are shown only at the anterior end and also the outline of the gut. 
Fig. 3-7. Represent the same specimen as figure 2 on the five days following 
the day of fission. In figure 4 the eyes are beginning. In figure 5 the 
gut rami have united anteriorly and the rudiment of the pharynx can 
be distinguished. In ligure 6 the development of the new median 
anterior gut ramus has progressed quite far but the gut is not shown 
in the posterior end of the specimen. In figure 7 the head is well 
formed, but the pharynx, which is shown without the gut, is still too 
far forward. 
Fig. 8. A worm developed from a tail piece like figure 2, as it appeared the 
8th day after the normal fission. 
Figs. 9, 10. A tail piece of P. maculata the third day after its normal fission 
and again on the 19th day to show the change of proportions. In 
figure 10 the gut is not shown. 
Fig. 11. The outline of the posterior end of a head piece of P. maculata on 
the day of normal fission and drawn over this the outlines (2, 3, 4, 5, 
, 6, 7) on the six succeeding days. 
Fig. 12. A tail piece on the day after the normal fission, showing a peculiar 
condition of the right gut ramus. 
Figs. 13, 14. A tail piece on the day after fission and again on the third day 
after, to show remodeling of the gut. 
Fig. T5. The anterior end of a tail piece on the day after normal fission as it 
appears when fully expanded. 
Fig. lG-18. The same tail jDiece on the 3d, 4th, and 5th days after normal 
fission. 
