Title Studies on the Development of Annelida Polychaeta I (With 17 Plates and 33 Textfigures) Author(s) OKUDA, Shiro Citation 北海道帝國大學理學部紀要, 9(2), 115-219 Issue Date 1946-05 Doc URL http://hdl.handle.net/2115/27055 Type bulletin (article) File Information 9(2)_P115-219.pdf Instructions for use Hokkaido University Collection of Scholarly and Academic Papers : HUSCAP Studies on the Development of Annelida Polychaeta P) By Shiro Okuda Akkeshi Marine Biological Laboratory (With 17 Plates and 33 Textfigures) Contents PAGE 1. Introduction ................................................. 117 II. Material and methods ....................................... 118 III. Development of Lumbriconcrcis latreilli Audouin et M. Edwards.. 120 1. Breeding habit ......................................... 120 2. Development within spawn-mass ......................... 121 3. Metamorphosis ......................................... 122 4. Early bottom stages .................................... 123 5. Formation of bristles ................................... 126 6. Notes on the spawning habits of Eunicidae ................ 127 7. General accounts ....................................... 128 IV. Development of Neanthcs sp. ................................• 130 1. Breeding habit ......................................... 130 2. Development within spawn-mass ......................... UO 3. Early bottom stages .................................... 181 4. Formation of bristles ................................... 133 5. General accounts ....................................... 134 V, Development of Nainereis laevigata (Grube) ................... 135 1. Breeding habit ......................................... 135 2. Early larval stages ..................................... 135 3. Metamorphosis and early bottom stages .................. 136 4. Juvenile stages ......................................... 138 VI. Development of Haploscoloplos kerguelensis (McIntosh) ........ 139 1. Breeding habit ......................................... 139 2. Development within spawn-mass ............ '.' . .. 139 3. Pelagic stages .......................................... 141 4. Metamorphosis and early bottom stages ................... 14 5. General accounts ....................................... 142 1) Contributions from the Akkeshi Marine Biological Laboratory, No. 116 S. Okuda PAGE VII. Development of SPlo filicornis (0. F. lVIiiller) .................. 144 1. Breeding habit ......................................... 144 2. Development within spawn-mass ......................... 144 3. De~elopment in plankton ................................ 147 4. General accounts ....................................... 148 VIlI. Development of Cirratulus cinatus (0. F. MillIer) ............. 149 1. Breeding habit ......................................... 149 2. Early larval development ............................... 156 30 Metamorphosis and early bottom stages .................. ]51 4. General accounts ....................................... 154 IX. Development of Lanassa nuda (Moore) ........................ 155 1. Breeding habit ......................................... 155 2. Development within spawn-mas,; ........................ 156 3. Early bottom stages ................................... 158 4. General accounts 160 X. Development of Arcnicola clapu;1'c(W L(!vins('n .................. 161 1. Breeding habit ......................................... 161 2. Development within egg'-tub('. ............................ 163 3. Pelagic stages .......................................... 164 4. Metamorphosis and early bottom stage~ ................... 165 5. General accounts ................ : . .. 167 XI. Development of Potamilla m1/1·iops lVI arenzeller ................. 168 1. Breeding habit ......................................... 168 2. Pelagic stages .......................................... 169 XII. Development of Chone teres Bush ......... "................... 171 1. Breeding habit ......................................... 171 2. Development w'thin egg-mass ............................ 173 3. Pelagic stagps ....... .. 175 4. Metamorphosis ......................................... 175 5. Juvenile stages ......................................... 178 G, F'nrn1ation of bristles ................................... 179 7. General accounts ....................................... 180 XIII. Development of Spirorbis spiriflllnl Linr:e ...................... 182 1. Breeding- habit of S. spirill1l1 11 nnd S. m'pponicus .......... 182 2. Devrlopment within tube ................................ 183 3. Pelagic stages .......................................... 186 4. Metamorphosis and early bottom stages .................. 187 XIV. Development of Spiro'rbis nipponic'ls Okuda .................... 189 1. Development within opeTculum ........................... 189 2. Liberation of larvae from operculum ..•.................. 191 3. Pelagic stages .......................................... 191 4. Metamorphosis and early bottom stages .................. 192 Development of Annelida Polychaeta I 117 5. Juvenile stages ......................................... 193 6. General accounts ....................................... 194 XY. R{"umc alld conclusion ...................................... 195 XVI. Literature.......................................................... 207 I. Introduction Although a relatively large number of papers dealing with the early stages from the first cleavage to the trochosphere of Polychaeta are found scattered in literature, the contributions to our knowledge concerning the metamorphosis are comparatively scanty, and, more­ over, only a few attempts have previously been made to trace suc­ cessively the development by rearing larvae from eggs to metamor­ phosis. The chief important pioneer studies on the later development of Pclychaetc were made by Agassix (1885), Claparede et Mecznikow (1869), E. B. Wilson (1882), Fevv·kes (1885), Malaquin (1893), Hacker (1896), Gravely (1909), Herpin (1926) and others. Re­ cently Aiyar (1831), Day (1934, 1936), Nolte (1936, 1938) and Segrove (1941) have rendered a great service to our knowledge of the development of Polychaetes, but the most valuable contributions must be due to D. P. Wilson (1929-1936), who published a lot of the important accounts on the development of about a dozen species belonging to the various families. As already pointed out by Wilson (1926), the development of seventeen among thirty-six families of Polychaetes has been studied more or less in detail, but information as to the development of the rest remains, if any, fragmentary. Such being the case, it would accordingly be futile to attempt to give detailed diagnoses of larvae of different families ;]nd genen: of Poly­ chaetes and to observe the metamorphosis from the standpoint of the phylogenetic relationships. For the sake of affording a basis for more complete study on the Polychaete larvae, the present investigation has been carried out during the last two seasons at the Akkeshi Marine Biological Labora­ tory. The present study starts in general with the early trochosphere and finishes with the yO)Jng worm a few days after metamorphosis; the cleavage and very early stages having been excluded. The chief interest centres at the metamorphosis and a special 'attension has been paid to those characters which appear to have phylogenetic values respective to different larvae. The technical 118 S. Okuda terms which are adopted in describing different stages and larval organs existing during the development, are based on those defined by Hacker (1897) and Gravely (1909). Before going further it is with real pleasure that I have to offer my most grateful thanks to Prof. Dr. Tohru Uchida, through whose continued interest and encouragement the work has taken its present shape. The expense of the present investigation was partly defrayed out of a grant from the Foundation for the Promotion of Scientific and Industrial Research of Japan. II. Material and Methods The material forming the subject of the present investigation includes the following 12 species belonging to the 9 families. Eunicidae 1) Lumbriconereis latreilli Audouin et M. Edwards Nereidae 2) Neanthes sp. Ariciidae 3) Nainereis laevigata (Grube) 4) H ap7 oscoloplos kerguelensis (Mclntosh) Spionidae r:;\ V/ (0. F. Thlullcr) Cirratulidae 6) Ci1'r'Citulus cirratus (0. F. Muller) Terebellidae 7) LanassCI nuda (Moore) Arenicolidae 8) A 1'enicola claparedii Levinsen Sabellidae 9) Chone teres Bush 10) Potamilla myriops Marenzeller Serpulidae 11) Spirorbis spirillum Linne 12) Spirorbis nipponicus Okuda Development of Annelida Polychaeta I 119 Though diverse in the spawning habits, all of these species, with a f'ingle exception of the species, Potamilla myriops, lay their eggs in the form of jelly-mass which affords with both food and protection for the development of the larvae. Lumbricone1'eis latreilli, N eauthes sp., Haplo8coloplos kerguelensis, Spio filicornis, Lanassa 1I11da, Cirratulus cirratus and Chone teres collect their eggs in the mass of jelly, whatever the shape may be, attached to the ground or the sea­ weeds. The eggs of Nainereis laevigata are discharged in gelatinous ribbon~like clusters knit loosely together. Arenicola claparedii forms a tube-like egg-mass deposited around the parent's body. In Spirorbis spirillwn the eggs are laid inside the tubes of the parent, while in Sp. nip]Jonicus the operculum serves as a brood-pouch. Only in Potcmdlla myriops the sexual products are discharged directly into