Kogia Macleayii, _Gray_, _l. c._ p. 391; _Synops. Whales & Dolph._ p. 4. Physeter simus, _Owen_, _Trans. Zool. Soc._ vol. vi. p. 30, t. 10, 11, 12, 13, ♀ (not skeleton, t. 11. f. 2). Inhab. Australia, India. Length 10 feet, young. The difference between _Kogia_ and _Euphysetes_ does not depend on the sex of the animals. Mr. Krefft described a male, and Professor Owen a female specimen; the latter mistook the two drawings of the same specimen for the two sexes, deceived by certain additions surreptitiously made to Mr. Elliot’s drawings; but the additions, especially the penis, are not represented on the plates, and the artist (Mr. Willis) says he received no directions to leave out any part of the drawing, and accurately copied them. The measurements given in the paper do not agree with those in Mr. Elliot’s notes made from the living animal; and reference to them would have prevented all this confusion. 3. EUPHYSETES. Euphysetes, _Gray_, _l. c._ pp. 196, 215, 386, 392; _Synops. Whales & Dolph._ p. 4. Head moderate, blunt and high in front. Skull short and broad. The septum that divides the cavity of the crown of the skull simple, longitudinal, only slightly curved. Vertebræ 51: cervical 7 (all united into one mass), dorsal 14, caudal 40. Basihyal broad and flat, as in _Catodon_. 1. Euphysetes Grayii. Euphysetes Grayii, _MacLeay_; _Gray_, _l. c._ pp. 218, 392; _Synops. Whales & Dolph._ p. 4. Physeter simus, _Owen_, _Trans. Zool. Soc._ vol. vi. t. 11. f. 2 (skeleton only). Inhab. Australia. Suborder IV. SUSUOIDEA. Susuoidea, _Gray_, _Synops. Whales & Dolph._ p. 4. Head beaked. Nostrils longitudinal, each covered with a valve (the right often obliterated). Teeth in upper and lower jaws, compressed. Crown of skull covered with a bony arch. Pectoral fin broad, truncate. Fingers 4, nearly equal, the outer the shortest. Family 8. PLATANISTIDÆ. Platanistidæ, _Gray_, _l. c._ pp. 62, 220; _Synops. Whales & Dolph._ p. 4. Platanistinæ, _Flower_, _Trans. Zool. Soc._ vol. vi. p. 114. Head long-beaked. Jaws slender, compressed. Skull—crown covered with the converging arch and reflexed edges of the maxillaries. “Costal cartilages not ossified. The tubercular and capitular articulations of the ribs blending together posteriorly. Cervical vertebræ all free. Pterygoid bones thin, not conforming in their mode of arrangement with either of the other sections. Jaws very long and narrow; both with numerous teeth having compressed fangs. Symphysis of mandible very long, exceeding half the length of the entire ramus. Orbit very small. Lachrymal bones not distinct from the jugal. Pectoral limbs large. Dorsal fin rudimentary. Maxillary bones supporting large bony incurved crests. No cingulum or tubercle at the base of the crown of the teeth. Pectoral fins truncated. Visual organs rudimentary. External respiratory aperture longitudinal, linear.”—_Flower._ 1. PLATANISTA.