PLANKTON OF THE WOODS HOLE REGION 
131 
the Fisheries dock. In this case, as in the case of N. limbata, free-swimming larvce 
appeared in great numbers in the tow, but few adults were taken. The usual 
swarming season for N. limbata ranges from June to September. A few adults of 
N. pelagica were taken during the year, but none of these contained ripe sex products. 
The breeding season of this species is in August and September. Platynereis 
megalops is also commonly taken at the surface from July to September. Although 
the young were taken on several occasions, but one adult appeared in the collections 
ei U ci u 
at at u u at it at u u 
fi ^ u a> at i-i u jstiuu 
^3 G at St -o oi -ti e at J3 JO 
«a>a>.oS6*3.ar-i <B at J3 e 8 
>>p4>oa>ai » u o -ri iu>>3-poo>«t 
•-><;^OOSQ►^^«<a•a;S1'^•-s■B:toOa5a 
Amphi trite ornata 
Arabella opallna 
Autolytus oomutTis 
Autoly-tus omatus 
Autolytus alexandri 
Autolytus emertoni 
Autolytus varians 
Autolytus longisetosls 
Dodecacera concharum 
Harmothoe Imbricata 
IchthyoMella rapax 
Lepldonatus squanatus 
lajTval L.squaraatus 
Lumbrlnerls tenuis 
Magelona rosea 
Mereis linbata 
Nereis pelagica 
Nereis vlrens 
Nephthys buoera 
Odontosyllis luoifera 
Odontosyllls sp. 
Paedophylax dispar 
Phyllodoce catenula 
J?hyllodoce gronlandica 
Platynereis megalops 
i?odarke obscura 
Spio setosa 
Telepsavus lai^ae 
Tomopterus helgolandlca 
Unidentified larvae 
Fig. 33.— Occasional occurrence of annelids in surface collections from June, 1922, to May, 1923. 
0, single specimen taken 
of the past two summers. All of the members of this family undergo extensive 
physical changes in adapting themselves for pelagic life during the breeding period. 
The anterior, nonsexual part remains the same, but in the posterior, sexual region 
the parapoda become broad and flat and the chiette increase greatly in length. 
In this form the worm is known as Heteronereis and is able to swim very rapidly. 
In contrast to the Nereidse stand the families Syllidse and Hesionidfe. The 
different species of Autolytus carry their eggs and swim about for varying lengths 
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