STUDIES ON THE DYNAMICS OF MORPHOGENESIS 297 



TABLE 3 



Sets from three series {28, 29, and 31). Worms 12 — 15 mm. in length in good 

 condition. 



DIAGRAM PIECE 



TAILLESS 



NORMAL 



V.ilOLLS 



TERATOP- 



THALMIC 



WHOLES 



HEADLESS 



29 (20), 31 (20) 

 Total 40 piec- < 

 es each) 



28 (10 pieces 

 each) 



10 

 50 



10 

 20 

 30 



70 

 30 



40 

 40 

 60 



20 

 20 



50 

 40 

 10 



In the following tables the data of a number of other series 

 are given: the series numbers and the number of pieces in each 

 set are given in the first column of each table and the diagrams 

 in the second column show the levels of section and the relative 

 sizes of the various pieces. As in table 1 the numbers of the dif- 

 ferent groups are percentages. 



In the series 40 and 41 of table 2 the anterior part of the body 

 is not included. The two series show the differences resulting 

 from the separation of a given region into three and four pieces 

 respectively. The greater frequency of teratopthalmic wholes 

 and headless tails in series 40 is at once evident. 



Table 3, from three different series, gives the results for pieces 

 including approximately the middle half of the body: the upper 

 half of the table shows the results for division of this region into 

 two parts, the lower half or division into three. 



The factor of size and the regional factor both appear as in 

 tables 1 and 2. The frequency of normal wholes and of wholes 

 in general decreases with decreasing size of the piece: even in 

 these series, however, which do not include the extreme posterior 



THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 10, NO. 3 



