Vou.2} Torrey.—Hydroid Differentiation and Senescence. 320 
August 8, 9:45 am. Hydrotheea of No. 5 with 1 annulus 
immediately below it, supported on a segment of stem with an 
annulus next the cut (fig. 3). 
Result: regeneration according to the distal, not the local 
type. 
IlI.—Aueust 5, No. 10. Stem with 20 hydranths and ter- 
minal bud. 
Pedicel 1 with 5 annuli 
Pedicel 2 with 0 annuli 
Pedicel 3 with 0 annuli 
Pedicel 4 with 7 annuli 
Pedicel 5 with 5 annuli 
Pedicel 6 with 7 annuli 
Pedicels 7-9 with 3 annuli 
Pedicels 10-21 with 1 annulus 
11:10 am. Cut stem between 6 and 7. 
August 7, 10:30 am. No. 7 has regenerated in a manner 
practically identical with that of the preceding experiment. 
Result: regeneration according to the distal, not the local 
type. 
The three cases in the second category seem to show that the 
mid regions of the stems no longer possess the capacity to pro- 
duce the type of structure originally arising there, but that they 
do produce a type of structure peculiar to the latest formed 
portion of the stem. During their growth, the stems appear to 
have changed their character throughout their length. 
The facts belonging to the third category concern the cases 
of heteromorphosis from the proximal cut end of the stem. 
I.—Aueust 5, No. 4 (see above). 
August 8, 10 a.m. Heteromorphic stem. 
August 11. Heteromorphie stem with terminal hydranth. 
Immediately below the hydrotheca are 3 annuli. The rest of 
the stem is similar in all respects to the heteromorphic stem in 
fie. 4. 
IIl.— August 5, No. 8 (see above). 
August 11. Heteromorphic stem similar in all respects to 
preceding (1), with the exception that development had stopped 
before a hydranth had appeared. 
