18 MESOPLODON. MONODON 



25. bidens. [P/irse/c-r), Sowerby, Brit. Miscell., 1804, i, p. r. 



sowerbyi and so7verbiensis, Blainv. Nouv. Diet., ix. 181 7, p. 177. 



epidon, Desm. Mamm., 1821, p. 521, No. 786. 



dalei, Blainv. Bull. Soc. Philom., 1825, p. 139. 



micropteriis, Cuv. Regn. .^nim., 1829, i, p. 288. 



Type locality. Coast of Elginshire, England. 



Geogr. Distr. North Atlantic. 



Genl. Char. Head higher than broad, forehead swollen; beak 

 flat and rounded at tip. Eyes large; ear openings very small; pec- 

 toral small, ovate; dorsal elevated, falcate; tail triangular bi-lobed; 

 vertebrae, 38. 



Color. Brownish lead color, belly bluish ash. 



Measurements. Total length of male, 16 feet, female 15 feet: 

 length of her head, 2. 7 in. , pectoral, 1.6 in. ; dorsal, o. 10 in., height of 

 dorsal, .11 in. 



Fani. 111. Delpliiiiidae. 



F. W. True. A Review of the family DelphinidiC, Bull. V. S. Nat. 



Mus. 1889, No. 36, p. 1-191, pts. 1-47. 

 Scammon. The Marine Mammals of Northwest North America, 



1874, p. 40. 

 Facial portion of skull produced into a beak; teeth numerous in 

 both jaws; anterior ribs articulated to the transverse process by a 

 tubercle; sternal ribs ossified. Lacrymal not distinct from thejugal; 

 pterygoids short, thin, and form with a process of the palate the 

 outer wall of the post palatine air-sinus. 



Sub Fam. I. Delphinapterinae. 

 14. Moiiodoii. 



Monodon. Linn. Syst. Nat., 1766, p. 105. Type M. monoceras, Linn. 



Ceratodon. Briss. Regn. Anim., 1762, i, p. 231. 



Diodon. Storr. Prodr. Mamm., 1780, p. 42. 



Narvalus. Lacep. Hist. Nat. C6t., 1804, p. 163. 



Oryx. Oken. Lehrb. Naturg., 1815, p. 672. 



Teeth produced in two twisted ivory tusks, generally concealed 

 in the female, and in the male only a single tooth is greatly developed, 

 usually the one on the left side, projecting horizontally, pointed and 

 marked with spiral grooves. Head short, rounded; dorsal rudimen- 

 tary; pectoral short, broad. Pterygoids not meeting, but approxi- 

 mating posteriorly. Vertebra- distinct, 50. 



