１ 殻縁なめらか−−−−−−−−−−−−−−−−−−−−−−−−−−−−−２
２ 殻は直線的で殻縁がほぼ平行−−−−−−−−−−−−−−−-−−−−−-３
２ 殻形皮針形−−−−−−−−−−−−−−−−−−−−−−−−−−−−−７
３ 縦溝が殻の中央を通る−−−−−−−−−−−−−−−−−−−−−−−−−４
３ 縦溝が殻端で殻縁に偏る−−−−−−−−−−−−−−−−−−−−−−−−６
４ 中心域が斜めで長楕円形−−−−−−−−−[22] G. plagiostomum
４ 中心域が斜方形−−−−−−−−−−−−−−−−−−−−−−−−−−−５
５ 殻長200μm以上−−−−−−−−−−−−−−−[６] G. balticum
５ 殻長150μm以下−−−−−−−−−−−−−−−−−[15] G. fenestratum
６ 縦条線は粗い(16-17/10μm)−−−−−−−−−−−−−−[26] G. simile
６ 縦条線は中庸(18-22/10μm)−−−−−−−−−−[ ] G. rectum ナシ
６ 縦条線は細かく(22-26/10μm)，縦溝波打つ−−−−[８] G. diminutum
６ 縦条線は特に細かい(40/10μm) −−−−−−−−−−-[18] G. obscurum
７ 縦溝が殻縁に近づく−−−−−−−−−−−−−−−−−−−−−−−-−−-８
７ 縦溝が中央を通る−−−−−−−−−−−−−−−−−−−−−−−−−−−９
８ 小型で横条線が粗い(17/10μm以下) −−−−−[26] G. simile
８ 小型で横条線が中庸(20-22/10μ) −−−−−−−−−−−−−−−−−−−20
８ 中型で横条線は22-24/10μm，殻が薄く弱い−−−−−−[14] G. nipkowii
８ 中型で横条線がやや細かい(26-30/10μm)−−−−−−−−[18] G. obscurum
９ 中心域が大きく，斜方形または楕円形−−−−−−−−−−−−−−−−−−−10
９ 中心域が小さい−−−−−−−−−−−−−−−−−−−−−−−−−−−−-12
10 中心域に点紋あり−−−−−−−−−−−−-−−[17] G. reimeri
10 中心域に点紋なし−−−−−−−−−−−−−−−−−−−−−−−−−-−11
11 殻長150μm以上，縦条線粗い(10-12/10μm) −−[ ] G. attenuatum var. attenuatum ナシ
11 殻長115μm以上，縦条線中庸(21-24/10μm) −−−−-[５] G. attenuatum var. nipponicum
11 殻長100μm以下，縦条線細かい(25/10μm以上)−−−−−[19] G. obtusatum
12 殻端が急に細くなり，くちばし状に長くのびる−−−−−−−−−−−−−−−−13
12 殻端が徐々に細くなる−−−−−−−−−−−−−−−−−−−−−−−−−16
13 殻端の幅３μm以上−−−−−−−−−−−−−−−[20] G. wormleyi
13 殻端 の幅２μm以下−−−−−−−−−−−−−−−−−−−−−−-−−−−14
14 殻長140μm以上−−−−−−−-−−−−−−−−[30] G. fasciola var. tenuirostris
14 殻長140μm未満−−−−−−−−−−−−−−−−−−−−−−−−−−−-15
15 縦条線が粗い(15-16/10μm) −−−−−−−−-[13] G. sulcata
15 縦条線は中庸(20-24/10μm)−−−−−−−−−−−[11] G. fasciola var. fasciola
15 縦条線が細かい(27-28/10μm)−−−−−−−−−−−−[12] G. fasciola var. globifera
16 横条線が粗く，16/10μm未満−−−−−−−−−−−−−−−−−−−−−−17
16 横条線は中庸で16/10μm以上22/10μm未満 −−−−−-−−−−−−−−−18
16 横条線が細かく，22/10μm以上−−−−−−−−−−−−−−−−−−−−−22
17 殻長150μm以下−−−−−−−−−−−−−−−−[16] G. fonticolum
17 殻長250μm以上−−−−−−−−−−−−−−−−−[29] G. strigilis
18 縦条線が粗い，17-22 10μm −−−−−−−−−−−−−−−−−−−−−−19
18 縦条線は中庸，22-25/10μm −−−−−−−−−−−−[27] G. kuetzingii
18 縦条線が細かい，26-28/10μm −−−−−−−−-−−−−−−−−−−−−-21
18 縦条線が極めて細かくLMでは識別しにくい −−−−−−−−−[31] G. prolongatum
19 殻長100-200μm，幅15-20μm，縦条線17-20/10μm−[１] G. scalprum
19 殻は小型で殻長90μm未満，縦条線20-21/10μm −−−−-[２] G. acuminatum var. curta
19 殻は細長く殻端が尖円形，縦条線20-22/10μm−−−−[３] G. acuminatum var. gallica
19 線状皮針形，殻幅20μm以上，縦条線20-21/10μm −−−−[４] G. acuminatum var. lacustre
20 縦条線はやや粗く，20-22/10μm −−−−−−−−−[21] G. wansbeckii
20 縦条線は中庸，24-25/10μm −−−−−−−−−−−−−[28] G. spencerii var. curvula
21 殻長110μm以下 −−−−−−−−−−−−−−−−[23] G. procerum
21 殻長70-115μm，−−−−−−−−−−−−−−−−−−[32] G. peisonis
21 殻長130μm以上 −−−−−−−−−−−−−−−−−−−[24] G. pseudokuetzingii
22 縦条線は28-31/10μm−−−−−−−−−−−−−−−−−−−-−−−−−−23
22 縦条線が極めて細かくLMでは識別しにくい −−−−-−[７] G. beaufortianum
23 横条線が波打ち殻端では逆放射−−−−−−−−−−−−−[９] G. exilis
23 横条線は放射，中心節"Ｔ"形−−−−−−−−−−−−−−−−[19] G. obtusatum
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