The captain of one of Mr. Vautier’s ships, on his return from a voyage to the colonies, saw floating on the water, at the entrance to the English Channel, the body of a large animal entirely covered by birds (large and small gulls, etc.), which were devouring it. The ship approached the stray, and the captain, knowing that Mr. Abel Vautier was greatly interested in natural objects, had the head of the cetacean cut off, fastened it securely with a cord, and let it trail behind the ship. When he arrived at Caën he made a present of it to Mr. Vautier. The piece had at that time an appearance anything but agreeable. Mr. Vautier was especially fond of beautiful objects which please the eye, and hence he offered it to my father, saying, “You, who are an anatomist, can make better use of this than I can.” My father was unwilling to refuse the present, but neither he nor Mr. Vautier knew as yet of its extreme rarity. It is in fact, up to the present time, the only specimen which exists, and is a unique object in collections.[20] No additional specimens have been recorded from European waters or elsewhere, and much doubt has been thrown on the validity of the species, many zoologists regarding it as an adult of the commoner species _M. bidens_. Van Beneden remarked in 1888: The opinions of naturalists are divided as regards the identity of this ziphioid, which is unique up to the present time. In the eyes of some it represents an old male of the common _Mesoplodon_, in which the tooth, instead of developing near the middle of the jaw, has developed near the anterior extremity. This is the opinion of Doctor Fischer and others, who think that this unique specimen represents merely an individual modification and that consequently it should not figure in the list of species. We do not share this opinion. It is not impossible that this ziphioid may belong to the other hemisphere, and this would explain why only one single individual has been captured in Europe.[21] In view of the circumstances surrounding the discovery of the original specimen, it is of great interest to find that two of the specimens from the east coast of the United States represent the same species. As one of them is adult and the other young, the view that the type of _M. europæus_ is merely an old individual of _M. bidens_ is satisfactorily disposed of, as is also the opinion that it represents a singular individual variation. The two American specimens which represent _europæus_ are those from North Long Branch, New Jersey (adult female; skull, lacking rostrum and mandible, in the Museum of Comparative Zoology), and from Atlantic City, New Jersey (young male; skeleton, cast and photographs in the U. S. National Museum, Cat. No. 23346). SPECIFIC CHARACTERS. The species _europæus_ differs from _bidens_ in the following characters, which may be regarded as diagnostic: