頭胸(xiong)甲(jia)寬稍大于長,中(zhong)等隆(long)(long)起,前(qian)寬后窄(zhai),表面較光滑,但(dan)密覆短毛,分區(qu)(qu)顯著:肝(gan)區(qu)(qu)較凹。前(qian)鰓(sai)區(qu)(qu)周圍具深溝,中(zhong)、后鰓(sai)區(qu)(qu)隆(long)(long)起。中(zhong)胃區(qu)(qu)兩側各具一深斑點狀凹陷(xian)及細(xi)溝。尾胃區(qu)(qu)小(xiao)而(er)明顯。心區(qu)(qu)凸(tu),其前(qian)緣(yuan)具一“V”形缺(que)刻。額窄(zhai),由一“V”形缺(que)刻分成兩齒(chi)(chi)。內(nei)口溝隆(long)(long)脊不突出(chu)(背面不可(ke)見)。內(nei)眼窩齒(chi)(chi)鈍,外(wai)眼窩齒(chi)(chi)呈三角形,下內(nei)眼窩齒(chi)(chi)短,齒(chi)(chi)端指向外(wai)方。
雌性螯(ao)足(zu)較小,對稱(cheng)。長節呈三棱形(xing),略為彎曲。腕節短(duan)小而隆(long)起。掌不膨大,寬為長的兩倍(沿前(qian)緣測量),指為掌長的2.5倍。?
前兩(liang)對步足瘦長,第(di)(di)(di)2對長于(yu)第(di)(di)(di)1對,長節邊緣(yuan)(yuan)(yuan)具(ju)細顆(ke)粒和短(duan)毛(mao)。腕節前緣(yuan)(yuan)(yuan)近末(mo)端有(you)毛(mao)。掌(zhang)節邊緣(yuan)(yuan)(yuan)及指節前、后緣(yuan)(yuan)(yuan)的(de)基(ji)半部(bu)有(you)剛毛(mao)。末(mo)兩(liang)對步足短(duan)小,位于(yu)背面,具(ju)短(duan)絨毛(mao)。第(di)(di)(di)4對足較第(di)(di)(di)3對瘦長,掌(zhang)節后緣(yuan)(yuan)(yuan)基(ji)部(bu)突出,具(ju)一撮短(duan)毛(mao),指呈鉤(gou)狀。?
雌(ci)性腹部呈長(chang)卵圓形(xing)(xing),分(fen)為5節(jie)(jie):第(di)2至第(di)5節(jie)(jie)愈(yu)合,但節(jie)(jie)線(xian)可辨,第(di)3至第(di)5節(jie)(jie)中部各具一(yi)條橫行隆脊。第(di)6節(jie)(jie)略呈半圓形(xing)(xing),寬為長(chang)的3倍,中部隆起,兩側具縱溝。尾(wei)節(jie)(jie)呈鈍三(san)角形(xing)(xing)。?
1185年(nian)春,日(ri)本日(ri)本平(ping)(ping)安時代,源氏(shi)(shi)(shi)和(he)平(ping)(ping)氏(shi)(shi)(shi)兩大(da)武士(shi)家(jia)族集團在壇(tan)浦決戰,平(ping)(ping)氏(shi)(shi)(shi)全軍覆沒(mei)。平(ping)(ping)清盛之(zhi)(zhi)妻平(ping)(ping)時子(二位(wei)尼御前)懷抱(bao)年(nian)僅八歲的安德天皇(huang)投(tou)海自(zi)盡,平(ping)(ping)氏(shi)(shi)(shi)武士(shi)也(ye)大(da)都(dou)葬身于瀨(lai)戶內海,史稱“壇(tan)之(zhi)(zhi)浦之(zhi)(zhi)戰”,
此后(hou)在該地發現的螃蟹(xie),后(hou)背紋(wen)露酷似憤怒的武士(shi)臉,被認為(wei)是平氏武士(shi)之亡靈(ling)所化(hua),因(yin)而被稱為(wei)“平家(jia)蟹(xie)”,或“武士(shi)蟹(xie)”,
其實該蟹種在(zai)中國沿海亦有分布,中國人因為其長得像關公(gong)的臉(lian)譜,而(er)習慣稱之為“關公(gong)蟹”。