Remarks on Saurocephalus , and on the Species which have been referred to that Genus

Abstract

I n the year 1824 Dr. Harlan described a portion of a fossil jaw which had been obtained in 1804, during an expedition up the Missouri, from what were believed to be Secondary rocks (Journ. Acad. Nat. Sci. Philad. 1830, vol. iii. p. 331). Dr. Harlan thought this specimen showed reptilian affinities, and compared it with certain species of Ichthyosaurus ; but, believing it to be generically distinct, he named it Saurocephalus lanciformis . Prof. Owen subsequently showed (‘Odontography,’ p. 130, pl. 55) that this specimen was to be referred to the group of Fishes. There has been so much misunderstanding about the genus Saurocephalus , to which certain specimens in this country have been erroneously referred, that it has been thought desirable to bring together all the known facts, in order, if possible, to correct the synonymy of the species. Dr. Harlan ( l. c. p. 335), after giving the measurements of the bone above mentioned (now known to be a maxilla), says :—“There are eighteen teeth in different states of preservation; the longest are seven tenths of an inch, two tenths only projecting above the bone, the projecting part enamelled, smooth, and shining, lanciform; the edges are very sharp. . . . The bodies of the teeth are all hollow, and are firmly fixed in a longitudinal groove, there being no distinct separate alveolæ. The bodies of the teeth are in close contact throughout . . . . The body of the bone is not perforated by a canal for the inferior maxillary nerve