(From Leunis, after Zeller.)
Diplozoon (Gr., 'double animal'), a remarkable flat worm or Trematode. It consists of two organisms fused together. The embryo, known as Diporpa, is ciliated and free-swimming, but soon relapses into parasitism. It loses its cilia, settles on a minnow's gills, loses its eyes, and remains for weeks or months like many another Fluke (q.v.). Finally, however, a curious phenomenon occurs. One individual moors itself by its ventral sucker to a conical knob on the back of another, 'which thereupon so twists itself as to fix the first individual in the same manner.' The cones and suckers are closely fused, but otherwise the second- arily twin animals remain independent. This double Trematode well deserves its name of Diplozoon paradoxum. See Zeller, Zeitschr. f. wiss. Zool. xxix. (1877).