Macleayius australiensis, _Gray_, _l. c._ pp. 105 (figs. 10, 11), 371 (figs. 74, 75); _Synops. Whales & Dolph._ p. 2. Inhab. Australian seas. Atlas vertebra—the width, measuring from the extremity of the lower processes, 28½ inches; width of the atlas 25 inches; height from the base of atlas to top of crest 18 inches. Thickness of last cervical vertebra 10 inches. 2. Macleayius britannicus. B.M. Macleayius britannicus, _Gray_, _Ann. & Mag. N. H._ 1870, vi. pp. 198 & 204. Balæna biscayensis, _Van Beneden_ (part.), _Ostéogr. Cét._ tab. 7. fig. 7 (copied from _Gray_, _Cat. Seals & Whales_, p. 83, fig. 3). Balæna britannica, _Gray_, _Ann. & Mag. N. H._ 1870, vi. p. 200. Inhab. Lyme Regis, Dorsetshire. Cervical vertebræ of _Balæna_ from Lyme Regis (Gray, Cat. Seals & Whales, p. 83, f. 3) copied on plate of _Balæna biscayensis_, Ostéog. Cét. t. 7. f. 7. Dredged up at Lyme Regis. The lateral processes of this bone are much more like those of _Macleayius australiensis_ than those of any other species; yet it differs in the outer edge of the broad lateral process being oblique, narrowed towards the base, and in the lower lateral process being shorter, turned up at the end, and the outer end obliquely truncated and subangular below. This massive vertebra has no affinity with _B. biscayensis_, and indicates the existence of a completely different new species of Right Whales, which appears to be an inhabitant of our seas. Suborder II. BALÆNOPTEROIDEA (_cf._ p. 36). Balænopteridæ, _Gray_, _l. c._ pp. 61, 106. Balænopteroidea, _Gray_, _Synops. Whales & Dolph._ p 2. Head moderate. Body elongate. Dorsal fin distinct, rarely wanting. Belly longitudinally plaited, rarely smooth. Baleen short, broad. Maxillary bones broad. Pectoral fin lanceolate; arms elongate; radius and ulna much longer than the humerus. Fingers 4, subequal. Vertebræ of the neck free, or partially united. Tympanic bones oblong or ovate. Family 2. AGAPHELIDÆ. _Scrag Whales._ Head moderate; body elongate; hinder part of the back keeled and notched. Cervical vertebræ free. Pectoral fin lanceolate. Fingers 4. Throat without plaits. No dorsal fin. Ribs single-headed. Mr. Cope “mentioned that he had an opportunity of examining a portion of a specimen of the Scrag Whale of Dudley, _Balæna gibbosa_ of Erxleben, and ascertained that it represented a genus not previously known. It was a Fin-back Whale; but without dorsal fin or throat-folds, resembling superficially the genus _Balæna_. The _baleen short and curved_. The genus was called _Agaphelus_.” 1. AGAPHELUS. Cervical vertebræ free. Fingers 4. Throat without plaits. No dorsal fin. Ribs single-headed. Scapula with acromion (Cope, Proc. Soc. N. Sc. Phil. 1869, p. 16). Agaphelus, _Cope_, _Proc. Soc. N. Sc. Phil._ 1868, pp. 159, 225; _Gray_, _Ann. & Mag. N. H._ 1870, vi. p. 200.