A Sacconereis “captured by the tow-net in the Firth of Clyde,” according to W. C. McIntosh (1908, p. 223, Fig. 5 f.), differs from any described female bud of Autolytus, or of its allied genera such as Myrianida or Proceræa of Ehlers, especially in respect to the shape and number of ovigerous sacs, which the animal carries on its ventral side. “It appears to be fully a quarter of an inch in length, and is readily discriminated by the absence of the single ventral egg-capsule, the ova being borne in eight conspicuous globular or pear-shaped sacs.”