ピレネー山脈でえたCymbella microcephalaの形態学的変異

抄録

The material examined was taken from the Pyrenees in Spain. Almost 360 specimens were analyzed comparing with the specimens from Cuzco (Peru) and Taitong (Taiwan). The margins of the valve are almost parallel in the specimen s from the Pyrenees, while they are mostly convex in those from Cuzco and Taitong. Though the valves are mostly symmetry with respect to the raphe in the specimens from the Pyrenees, they are often asymmetry in those from Cuzco and Taitong. As to the arrangement of the striae at the both ends, it is radiate in the Pyrenees (ca.99%) and parallel in Taitong (ca.72%). Three types, radiate, parallel and irregular are observed with almost the same frequency (ca.32 %,36 % and 25%respectively) in the samples from Cuzco. The breadth of a valve in the Pyrenees is the narrowest among the three places. The specimens from Taitong have the widest valves. As to the density of the striae, similar density is observed in the specimens from Taitong and Cuzco and denser striae are observed in those from the Pyrenees.