Note 581 — Chapter XVI

There is a marked difference between the internal structure of the teeth of true Saurians and of Sauroid Fishes. In the former, as well as in the Enaliosauria, the dentine consists of tubes radiating from a slender central pulp-cavity to the periphery of the tooth, without any intermixture of vascular canals. In the sauroid fish (Dendrodus) the central pulp-cavity is produced into numerous irregular canals, from which vascular sinuses radiate to the periphery, sending off branches generally at right angles throughout their entire course; thus, there is an extensive distribution of the vascular system through the body of the tooth, which does not exist in any saurian reptile; the nearest analogy is in the labyrinthine teeth of the gigantic fossil batrachians. (Owen: Odontography; and Art. Teeth, Cyclop. Anat.)