AUTHOR’S ABSTRACT OF THIS PAPER ISSUED 
BY THE BIBLIOGRAPHIC SERVICE, MAY 9 
REGENERATION IN THE ANNELID NERVE CORD 
ADA R. HALL 
Zoological Laboratory of the University of Oregon 
SEVENTEEN FIGURES (SIX PLATES) 
CONTENTS 
RTNECUITCHLON PSE HeNet aye ee. coe CASALL. Mehta PARES Meta Se Bae aco ASEM oe nee ies 163 
DiscissrOnwoisuhesprOWleMminme a. kes er ie eee eter etnies olage cis pes cyeiscyens Sk 164 
JN. IMeNiGribletnrcl aero lay, ocamer oscmucce poo ecue.s LoOmb ceo Sescesad Sc 164 
COHEN CE cee epee ts Okan etre eats oe Bln. cemn ye oe wee ain nicioe © earns & 165 
Geherenernvionraiter SSimiplereMts ool: 82 se ets kle ed «cee eantde sin 167 
(PA SOUTCeLOR ileucleaiinix CCllSmpr ere. cee. 8 ous, 5 fers aisycbets ciojererere = apete 167 
PR ECrOWUNROMMeTE VeRO CTSio® sakes arare ke dies 2 oe cieays S-evothe teats a ole wes 172 
Ser SUMMA nyRO MSM plese yenecaGlOles e:- te yeris an es oeeya tase 173 
D. Regeneration when two to four segments are removed............... 173 
foe NOLEVETAWOLKG yer ats Hein hie. 4 syd WS? Chern con tae ts See daie oe beat et 173 
PemresentmexpenilmM ets seas ve thie oe orate acs s. ced cious eas) Stoaeus ted 174 
3. Summary of regeneration—several segments removed........... 175 
GEnerAINCONCIISTONS A ate Falah ete heh Fore alas oy ANd Sette Sab Memes sees 176 
ID ISEUSSTONBOMTESUMGS sf a.crec ic) 6 oon yes chs ore O cick? NA NIEISS IS SIP iy hoe Se 176 
DSL AGRI TT EN A htc eer ones BIA Recon. eee ise ae a wee ear 178 
INTRODUCTION 
The earliest work on regeneration in the earthworm is con- 
cerned with the general growth of an individual or with the 
grafting together of parts of the same or different species of 
worms. Heschler (98) and Rand (’08) have outlined the 
steps in the process when a new head is formed, four or five 
segments having been removed. They consider that the ecto- 
derm is responsible, at least in part, for the growth of the new 
nerve material. Friedlander has shown that the pull of the 
longitudinal muscles will cause coordinated rhythmical move- 
ments in two pieces of worm when their only connection with each 
other is a piece of string. Biedermann shows that the nerve 
cord is important in that it may carry impulses through several 
163 
THE JOURNAL OF COMPARATIVE NEUROLOGY, VOL. 33, NO. 2 
