Rastrites
in palæontology, a genus of Graptolites or Rhabdophora. The polypary consists of a slender axial tube, having on one side a row of cellules, or hydrothecæ, separate and not overlapping. The typical species is R. peregrinus, which, with R. triangulatus, is found in the S. of Scotland. Etheridge makes a zone of R. peregrinus in the Upper Birkhill or Gray Shale group of the Lower Llandovery. Found also in Bo- RAT hemia (where it is said to extend to the Upper Silurian), in Saxony, etc.