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Record: oai:ARNO:318381

AuthorR. Horst
TitleOn a gigantic Nereis (Ner. ijimai Iz.) from Japan
JournalZoologische Mededelingen
AbstractAmong the Polychaeta of the Leyden Museum I met with a large Nereis-specimen, presumably collected in Japan, that in the structure of its parapodia so much agrees with Ner. ijimai1) described by Izuka from that country, that in my opinion it must be identified with this species, though there are some discrepancies in the armature of the proboscis.
Nereis ijimai, like as Ner. oxypoda Marenz, Ner. virens Sars a. o. are characterized by the presence of a large, foliaceous dorsal ligula at the parapodia of the median body region and were ranged by Kinberg in his genus Alitta2). Unfortunately Izuka had only a single female specimen at his disposal, that was sexually mature and showed some epitocous transformation after the 40th parapodium by the presence of cultrate setae and epitocous lamellae; it had a length of 390 mm. and consisted of 215 segments. Our specimen reaches 350 mm. and the number of segments amounts to about 200; it is also a female, filled with small eggs; however it is not entirely mature and there are neither paddleshaped bristles nor epigamous lamellae. The proboscis was everted and its armature consists of: I = a single indistinct paragnath (in Izuka's specimen absent).
II = a crescent, distichous group of 9 to 10 paragnaths (in Izuka's specimen in small groups).
IV = a crescent group of 16 to 18 paragnaths, the anterior ones arranged in a single row (in Izuka's spec. 3 or 4 in a group).
III = a single paragnath (in Izuka's spec. absent).
V = 0 (in Izuka's spec. absent).
VI = 8 to 10 paragnaths in a round group (in Izuka's spec. 6
Document typearticle
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