Family 9. INIIDÆ.
Iniidæ, Gray, l. c. pp. 62, 226; Synops. Whales & Dolph. p. 4.
Platanistidæ (Iniinæ), Flower, Trans. Zool. Soc. vol. vi. p. 114.
Fluviatile. Head beaked; beak bristly. Teeth in the jaws, rugulose, crowns with an internal lobe; permanent. Pectoral fin large, elongate, subfalcate. Back keeled behind, without any dorsal fin. Skull—jaw compressed; symphysis of lower jaw elongate, extending for more than half its length. Overlooking the form of the blower, Mr. Flower places this genus with Platanistidæ.
Vertebræ 41. C. 7. D. 13. L. 3. C. 18. The smallest number of any Cetacean known.
“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.”—Flower.
“Maxillary crests absent, or very slightly developed. Many of the teeth with a complete cingulum or a distinct tubercle at the base of the crown. Pectoral fin ovate, obtusely pointed.”—Flower.
1. INIA.
Inia, Gray, l. c. p. 226; Synops. Whales & Dolph. p. 4; Flower, Trans. Zool. Soc. vi. p. 87.
Cervical vertebræ free: the first with an inferior posterior process, bifid at the end; lateral processes very short: the second with a strong dorsal process. Dorsal vertebræ with very high dorsal processes. Scapula very high, with very long acromion and coracoid processes. The arm-bone short. Forearms thick and short, scarcely so long as the upper arm-bone. Metacarpal bones seven, imbedded in cartilage. The second and third fingers very long, with six phalanges; the first finger very short, of two phalanges; the fourth strong, short, about as long as the first two phalanges of the third finger, of four phalanges; the fifth finger very short, slender, of three phalanges. The breast-bone ovate, scutate, notched in front.
1. Inia Geoffroyii.
Inia Geoffroyii, Gray, l. c. pp. 226, 393; Synops. Whales & Dolph. p. 4; Flower, Trans. Zool. Soc. vi. p. 87, t. 25, 26, 27 (skeleton).
Delphinus amazonicus, Spix, Reise in Brasil. t. iii. pp. 1119 and 1113, fig. 34 (bad).
Inia Geoffrensis, D’Orbigny, in Ann. Mus. Paris, vol. iii. p. 23; Gervais, Ostéog. Cét. t. xxxii.
Inhab. Brazil, river Amazon.
“The number of the teeth in the different specimens of Inia examined shows a considerable range of variation, presuming that they all belong to one species. In the one now described there are R. 26, L. 26 / R. 25, L. 27 = 104. The larger specimen in the British Museum, from Ega, has 28-28/26-27 = 109, and also two minute rudimentary teeth in the gum behind the last in the left maxilla. In the smaller skull from the same place there are 29-26/28-27 = 110. In the skull in the Paris Museum, brought by D’Orbigny, there are, according to Gervais, 33-33/33-33 = 132; but in the type specimen in the same museum, taken from Lisbon, the number is given by De Bainville as 26-26/26-26 = 104. In the Berlin skull the teeth are 34-32/33-32 = 131. Von Martius, in his diagnosis of the species, gives 28-28/29-29 = 114.”—Flower.