Character;Species;"S. composita";"S. corticiformis";"S. longicaudata";"S. oviformis" Source;"Tokioka (1951)";"present study";"Beniaminson (1975)";"Skalkin (1957)";"Redikorzev (1913)";"Sanamyan (2000)" "Zooid length (mm)";12;12–50;15;40;10;10–30 "Zooid width (mm)";8;8;5;7.5;4;4–8 "Posterior extension of zooid long (+) or short (‒)";‒;"‒ / +";‒;+;‒;‒ "Number of oral tentacles";30;30–35;20;30–35;20–25;20–25 "Number of size-classes of transverse vessels";?;2;1;2;1*;? "Stomach internal wall present (+) or absent (‒)";?;+;+;+;+;+ "Intestinal loop";?;J-shaped;J-shaped;J-shaped;J-shaped;J-shaped "Number of anal lobes";0;0;2;0;2;2 "Number of gonadal branches";2–5;2–5;4;3;2;2–4 Locality;"Akkeshi Bay";"Akkeshi Bay";"Kunashiri Island";"South Kuril Islands";"Ul’banskij Bay";"Sea of Okhotsk"