I n the first edition of his famous work, the “Systema Naturæ,” published in 1736, the great Swedish naturalist, Linnæus, proposed the name Graptolithus for certain natural markings occasionally found upon stones, which are not true fossils, but are mere superficial stainings, having the deceptive appearance of being organic remains. In the twelfth edition of the “Systema,” however, Linnæus unwittingly figured and described two true fossils under the head of Graptolithus. One of these, his Graptolithus scalaris, was founded upon some strange markings found upon pieces of broken stone collected in Scania, in the south of Sweden. In 1821, Dr. Wahlenberg collected some specimens of the Graptolithus scalaris from Linnæus’ original localities. These he submitted to a careful examination, and reached the conclusion that they were the remains of fossil Orthoceratites. Through the subsequent researches, however, of Nilsson, Portlock, and Barrande, who discovered and studied many genera and species of fossils of the same type as the original Graptolithus scalaris, it has been demonstrated that these so-called Graptolithus or Graptolites are the petrified remains of Hydroida, allied to the modern Zoophytes of our sea-coasts. These fossil Graptolites are all plant-like forms, and are of many different shapes—linear, leaf-like, tree-like; simple and compound. They all show peculiar notches or teeth upon their outer margins, and are now transformed into shining carbonaceous matter. They are separated by palæontologists into two main groups—the Rhabdophora and the Cladophora. The Rhabdophora stand almost alone in the animal world in the possession of a peculiar rod or