Note on the Caudal Vertebra of a Cetacean discovered by Prof. Judd in the Brockenhurst beds, indicative of a new Type allied to Balænoptera ( Balænoptera Juddi )

Abstract

The vertebra submitted to me by Professor Judd belongs to the caudal region; and although in a new type there may be some doubt concerning the exact place in the series, it may be affirmed to have been about the eighth caudal, and certainly not later than the twelfth. The vertebra is probably distinct from all recent and fossil genera; but its characters are altogether in harmony with the Balænidæ; and the specimen indicates a genus much more closely related to Balænoptera than to Balæna , so far as can be judged from a single vertebra. This affinity is especially shown in the character of the base of the centrum, which had the facets for the chevron bones very small, and also in the general character of the neural arch, which is much less massive than in Balæna . The differences from the great Balænoptera musculus on the other hand are clearly defined, and appear to consist in the remarkably forward position of the neural arch (fig. 2), since in Balænoptera it does not usually reach the anterior sutural margin. The depressed transversely ovate outline of the neural canal (fig. 3) is another distinctive character, since in Balænoptera the neural canal is higher than wide. The neural spine also appears to be much less developed than in the recent genus, though, as the hinder part of the neural arch is broken away, this character cannot be positively affirmed. The centrura is relatively much shorter (fig. 2) ; the facets and ridges on