Any of several dogfishes lacking a spine in front of the dorsal fin, especially a species(Mustelus canis) found abundantly on the American Atlantic coast and often used in classrooms for dissection and study. 大星鲨：背鳍前面没有背骨的各种鲨鱼中的一种，特别指（白斑星鲨星鲨属） 种的动物，常常出没于美国大西洋岸并在教室里供制作标本和研究