4 BULLETIN 73, UNITED STATES NATIONAL MUSEUM. 



specimens represent Mesoplodon europxus (Gervais). This is a very interesting dis- 

 covery because the latter species has been known hitherto only from a single skul 

 and its validity has been frequently questioned. The Annisqiyim specimen, as will 

 be seen later, presents characters which appear to ally it to M. densirostns. 



MESOPLODON BIDENS (Sowerby). 



Physeter bidens Sowerby, British Miscell., 1804, p. 1; Trans. Linn. Soc. London, vol. 7, 1804, 



p. 310. 

 Delphinus sowerbenm Blainvii.le, Nouv. Diet. Hist. Nat., 2d ed.. vol. 9, 181,, p. 177. 

 Delphinus sowerbyi Desmarest, Mammalogie, pt. 2, 1822, p. 521. 



The only specimen from the Atlantic coast of the United States which can 

 with certainty be referred to this species is the one from Nantucket mentioned on 

 page 3. Prof. L. Agassiz's original notice of it is so brief that it is quoted in full 

 below : 



Professor Agassiz also brought to the notice of the Society the discovery of a Cetacean, new to 

 America. The skull was exhibited, and its peculiar features pointed out. It was obtained on the 

 coast of Nantucket by Messrs. H. M. and S. C. Martin, of Roxbury. It belonged to thegenus ifesoplodon, 

 as characterized by Gervais, and ought to be separated from the fossil Ziphius, described by Cuvier. 

 Professor Aga-s-^^iz, "however, questioned whether Mesoplodon was not identical with Delphinorhynchus, 

 previously described by Dc Blainville. The specimen found at Nantucket measured 16 feet in length.* 



SKULL. 



The skull of this Nantucket specimen, which I have before me, is thoroughly 

 adult. That the specimen is a female is probable from the fact that the teeth (one 

 of which is preserved), though fully developed, are only two-thirds as broad and 

 three-fourths as long as those of Sowerby's specimen (the type of the species), 

 which was an adult male.* The skull is 765 mm. long, and about .30 mm. are lack- 

 ing from the end of the beak, so that the original length was about 795 mm. It 

 appears to be, therefore, rather the largest skull of the species of which there is any 

 record. The specimen itself, according to Dr. J. A. Allen, was 16 feet 3 inches 

 long. ' The largest European skull appears to be the one in the Edinburgh Museum, 

 described by Sir William Turner in lcS72.'i The length of this is 749 mm. The 

 specimen was a female, but tliough the skull is so large, the mesirostral cartilage was 

 not ossified, and the individual was, therefore, probably not thoroughly adult. 

 Two other European specimens, of which the total length was almost identical 

 Avith that of the Nantucket specimen, were (1) the adult female obtained at Over- 

 strand, England, in 1892, and recorded In^ Southwell and Maimer "^ (length 16 feet 



oProc. Boston Soc. Nat. Hist., vol. II, 1866-68, p. 318. 



b One of the teeth of Sowerby's specimen is figured by Lankester in Trans. Roy. Micr. Soc, new 

 ser., vol. 15, 1867, pi. 5, figs. 1, 2. 



cBuU. Mus. Comp. Zool., vol. 1, 1869, p. 205. 



d Trans. Roy. Soc. Edinburgh, vol. 26, 1872, p. 771. 



'Zoologist, ser. 3, vol. 17, Feb., 1893, p. 42; Ann. and Mag. Nat. Hist., ser. 6, vol. 11, 1893, p. 275. 



