\Vou.2] Torrey.—Hydroid Differentiation and Senescence. 325 
Pedicels 1, 2 with 3 annuli 
Pedicels 3-8 with 4 annuli 
Pedicels 9-11 with 3 annuli 
Pedicels 13-17 with 1 annulus 
Pedicel 18 with 0 annuli 
Pedicel 23 with 0 annuli 
Pedicel 24 with 1 annulus 
10am. Cut off terminal bud, 24, 23, and part of 22. 
July 28,10 a.m. New hydranth No. 22 regenerated within old 
eup, on a short stalk from which hydrotheca is separated by a 
single constriction and is therefore sessile. 
Result: regeneration is according to the local, not the basal 
structural type. 
Il.—July 26, No. 3. Stem with 17 hydranths and terminal 
bud. 
Pedicel 1 with 3 annuli 
Pedicel 2 with 3 annuli 
Pedicel 3 with 4 annuli 
Pedicel 7 with 1 annulus 
Pedicel 9 with 1 annulus 
Pedicel 11 with 0 annuli 
Pedicel 13 with 0 annuli 
Pedicel 15 with 0 annuli 
Pedicel 17 with not even nodal constriction 
12 m. Removed terminal bud, 17, 16, and part of 15. 
July 27, 9:15 a.m. No. 16 has regenerated as a bud on short 
stalk; no constriction whatever between latter and hydrotheca 
(fig. 1). Though there are two cut surfaces, but one bud has 
been formed, in place of the originally proximal individual. 
No. 16 developed later into a hydranth, the skeleton remaining 
in the same condition except for a slight general thickening. 
Result: regeneration is according to the local, not the basal 
structural type. 
III.—Aueust 5, No. 4. Stem with 15 hydranths and terminal 
bud. 
Pedicels 1-4 with 2 annuli 
Pedicels 5-11 with 1 annulus 
Pedicel 12 with 0 annuli 
Pedicel 13 with 3 annuli 
Pedicels 14-15 with 1 annulus 
Pedicel 16 with 0 annuli 
