Sibbaldius tuberosus, Cope, Proc. Acad. Nat. Sci. Philad. 1867, p. .
Sibbaldius laticeps, Cope, l. c. 1866, p. 297.
Inhab. North-east coast of America.
Family 5. BALÆNOPTERIDÆ. Pike Whales.
Balænopterina, Gray, l. c. p. 114.
Balænoptera, Gray, l. c. p. 114; Lilljeborg, Nova Acta Upsal. vi.
Balænopteridæ, Gray, Synops. Whales & Dolph. p. 3.
Dorsal fin high, erect, compressed, about two-thirds of the entire length from the nose. Pectoral fin moderate, with four short fingers. Vertebræ 50; cervical vertebræ sometimes anchylosed. Neural canal broad, trigonal. Ribs 11·11. The second cervical vertebra with a broad lateral expansion, perforated at the base. First rib single-headed. Lower jaw with a conical coronoid process.
1. BALÆNOPTERA.
Balænoptera, Gray, l. c. pp. 114, 186; Synops. Whales & Dolph. p. 3.