NOTES ON MYSID SYSTEMATICS (CRUSTACEA, MYSIDACEA) OF ARCTIC AND THE NORTH-WESTERN PACIFIC

Taxonomic results are presented of the studyng of the mysid collections (including type speciemens) deposited in the St.-Petersburg Zoological Institute. Pseudomma frigidum, Neomysis intermedia, Exacanthomysis arctopacifica. and Paracanthomysis spadix are treated as the junior synonyms of Pseudomma roseum, Neomysis awatschensis, Acanthomysis stelleri, and Paracanthomysis schikhotaniensis respectively. Gnathophausia gigas and G. ingens are removed from the genus Gnathophausia to form the genus Neognathophausia gen.n. Diagnosis of Neognathophausia gen.n.: Antennal scale whole, without the distal part and articulation; its external margin sawly jagged with 3-9 spines. Distal segment of the maxillula tentacle crescently curved. Dactyls of the 3-8 thoracopods lengthened lanceolate and armed with 8-10 spines (including the distal spine) nearly through the length of the inner margin. Epimeral plates of the VI abdominal segment knitted ventrally and form an indivisible plate with a deep cleft at the distal end. Revised diagnosis of Gnathophausia Willemouse-Suhm, 1873. Antennal scale with distinctly isolated distal part and more or less developed articulation; its external margin ended with single powerful spine is smooth or carries 1-4 small spines on the distal end only. Distal segment of the maxillula tentacle is straight, but can be aslant articulated with a basal segment. Dactyls of the 3-8 thoracopods widened, lanceolate; 3 spines situated at the distal part of the inner margin only, 1 spine can be in the middle of the inner margin, Epimeral plates of the VI abdominal segment ventrally not knitted with each other.