113 



bulletin: museum of comparative zoology. 



It will be observed from this table that, when the anterior zooid again 

 buds, the zone of budding occurs at the same distance from the anterior 

 end as in the first instance, i. e. in the same body segment. This is not 

 true, however, for the posterior zooid. There may be either an increase 



T&. "; 1. Cephalic segments (4) -f- pr'stm. 



A < 2 i 



2. Body segments (11 to 16), unchanged- 



>-_ — 3. Half-segment, producing the equivalent of 3 to 7.. 



 4 Half-segment, producing the equivalent of 1 



■" 5. Body segments (5 to 10), unchanged 



.'•■ 6. Preanal zone, producing 



+ -i-± 



'■•7. Anal segment, unchanged 



--3 

 '4 



••5 



- 6 

 -7 J 



>B 



Fig. I. 



Fig. II. 



or a decrease in the number of segments in front of the budding zone 

 as compared with the condition in the parent. This variability is per- 

 haps correlated with the rate of growth as dependent upon food, etc. 



It will be seen from the accompanying diagram (Figures I. and II.) 

 that the half-segment A, 3 (Fig. I.) produces A, 3-7 (Fig. II.), which 



