246 LILLJEBORG ON THE 



the caudal fin is but slightly forked in the hinder edge. The anus is under the dorsal fin. 

 There arc two pairs of teeth in the fore part of the lower jaw, more or less hidden in the gums ; 

 the hinder and outer pair are considerably smaller than the anterior, and are deciduous ; there 

 are also on each side of the upper and lower jaw a row of 12 — 13 very small and rudimentary 

 teeth, hidden and loose in the gums (Lacépéde and Eschricht). 



The skull has several peculiarities ; the upper jaw is prolonged in front into a narrow and 

 pointed beak. A very large compressed and longitudinal protuberance or crest arises posteriorly 

 and inside of the lateral angle of each superior maxillarj-, sloping in front, and having more or 

 less perpendicular sides, behind and inside. This protuberance is more developed in the older 

 than in the young specimens. The concavity behind these tuberosities is limited behind by a ver- 

 tically rising wall, formed, principally at least, by the superior maxillaries, the intermaxillaries, 

 the nasals, the frontal, and the occipital bones, and terminating above in a high lamboidal or occi- 

 pital crest. The ossa pterygoidea, on the lower side of the skull, are remarkable for their great 

 elongation. Eschricht has found a strongly-developed lachrymal bone, which is said to be absent in 

 other toothed-whales. The lower jaw-bones, viewed from the side, are curved like an S. Their 

 symphysis is rather long, but shorter than half their length. The skeleton is remarkable for the 

 small number of vertebrae, which have bodies of more than usual length; their spines arc verj' high, 

 and the transvei'se processes of the lumbo-sacral vertebræ and the anterior caudal vertebræ are 

 comparatively short, and directed forward on all. All the cervical vertebræ are united, and have 

 a common spinous process. The ribs are few in number. 



According to Eschricht's investigations it seems that only one or two species of this genus 

 are positively known ; these belong to the northern parts of the Atlantic, the North Sea, and the 

 Frozen Ocean. Only one species has, i;p to the present time, been found on the coasts of 

 Scandinavia. 



H. RosTRA'iTS, Pontoppidan. The Bottlehead. Swedish, "Nabbhval." 



Sufficient space hetween the tico pirotuljc ranees on the superior maxillary hones for at least one 

 of the same size hetween tlieni. 



Bal.ena rostrata oder Nkbbe-Hwai., E. Pontoppidan. Versucli cincr naturlicheu 



Historie von Norwegen, p. 233, 1754. 

 MoNODON spuRius, Groeul. Anarnak., O. Fabricius. L. c, p. 31. 

 The Bottle-nose-Whale described by Dale, J. Hunter. L. c, pp. 373 and 447, 



tab. xix. 

 Delphinus diodon, Laccpede. L. c, p. 309. 

 Hyperoodon Butskopf, Idem. L. e., p. 319. 

 L'Hyperoodon, G. Cuvier. L. c, p. 324, tab. xxiv, figs. 19 — 21. 

 Hyperoodon Butzkopf, F. Cuvier. L. c, p. 241, tab. is, figs. 1 — 3; tab. xvii, fig. 1. 

 Delphinus edentulus, J. A. Wagner. L. c, p. 360, tabs, cccxlvi, cccxlvii, and cccxlviii, 



%•!■ 

 Hyperoodon Butzkopf and wo^tv.x-yvm,. J. E.Gray. L. c, pp. 25 and 26, pi. iii, figs. 1 — 5. 



