8 DR. R. W. GIBBES ON THE 



ing those crowded together by Mr. Koch, a German collector, and exhibited by him 

 as the remains of a single individual, from a single locality, under the erroneous name 

 of HijdrarcJios. It is well known that most if not all of these gigantic bones belong 

 to the Zeuglodon, the supposed exceptions being some of the caudal vertebrae, 

 which may have pertained to another animal. The identity of the Zeuglodon 

 and Hydrarchos, was demonstrated to Mr. Koch himself, before he published his 

 description ; and subsequently Dr. Wyman of Boston confirmed and illustrated this 

 fact in a masterly manner. Prof. Miiller of Berlin, who is now engaged in examining 

 Mr. Koch's collection with a view to publication, has come to the same conclusion ; 

 on which point, however, no one could have a moment's doubt who has any know- 

 ledge of the subject.* 



1 have in my collection a large vertebra which was presented to me by Mr. Cooper, 

 of Claiborne, Alabama, and which is the specimen noticed by Mr. Buckley in the 

 American Journal of Science for July, 1846. It measures eighteen inches in length, 

 and twelve inches in diameter on the articulating surfaces ; and although destitute of 

 the processes and somewhat broken, it weighs sixty-five and a half pounds ! With 

 it I received several portions of ribs, corresponding in character with those described 

 by Dr. Harlan and Prof. Emmons. 



I have lately had an opportunity of examining the cranium of a small Zeuglodon, 

 (PI. V.) discovered by Prof Lewis R. Gibbes, of Charleston, and described by Prof. 

 Tuomey in the Proceedings of the Academy.f The characters of this skull afford 

 additional evidence that Prof. Owen was correct in assigning to the animal a place 

 among the Cetacea, for it shows a striking affinity to the genus Delphinus. Prof. 

 Tuomey thinks it belonged to a young animal ; but the solidity of the bones and the 

 tooth, with the apparent full development of enamel, incline me to a contrary belief. 

 Since I have seen Grateloup's description of Squalodon, and his figure, (PL I. fig. 5,) 

 I suspect the two may even prove specifically identical. The teeth are thinner, the 

 form of the crown more conical and the serratures more vertical, the crenatures 

 smaller and shorter, and the neck, at the insertion into the alveolus, more contracted 

 in the Charleston and Leognan specimens than in the other species now under 

 consideration. 



My supposed discovery of what I called Dorndon, described in the Proceedings of 

 the Academy for June, 1845, adds another species to this genus. In the notice I then 

 published, these remains appeared to me to differ generically from the Z. cetoides, 



* Mr. Lyell has published sufRcieiit evidence to show that Mr. Kocli's specimens weie obtained in various parts 

 of Alabama. This is further proved by a letter from Dr. Lister, of Alabama, published in the Proceedings of the 

 Boston Society of Natural History; and Dr. Dickeson, who has recently made a geological exploration of that slate^ 

 confirms the now proverbial fact, that the so-called Hydrarchos was obtained from several different and even distant 

 localities. 



t February, 1847. — Prof. Tuomey's description is republished in the present volume. 



