45 



D. Senedetta, D. Commersouii, D. niger and D. Per- 

 nettii, Lacep. 



D. Epiodon and D. uiongitori, Raffinesque. 



B. compressed. Symphysix of the lower jaw very long. 

 Dorsal none. Teeth in both jaws. Fluviatile. 



d. Skull with the maxillary bones bent up in front of 

 the blowers, and formiity a vault. The teeth compressed. 

 The paddles fan-shaped, truncated at the end. Platanis- 

 lina. 



Platanistina, Gray. 



Head convex, back compressed, curved up at the end. 

 Teeth compressed. Dorsal none ; back keeled in the 

 place of the fin, and obliquely truncate behind. Pectoral 

 fan-shaped, truncated. 



The Son Sou. Platanista Gangetica. 



Delphinus Gangeticus. Lebeck, N. Schrift. Berlin, 

 Aatur. iii. -280, t. 2. Home, Phil. Trans. 1818, 417, t. 20. 

 Roxbu ryh , Asiatic Researches, vii. 170, t. Cuvier, Oss. 

 Fos. V. t. 22, f. 8—10. 



Delphinorhynchus gangeticus, Lesson. Platanista gan- 

 geticus. Gray, Illust. Indian Zool. t. F. Cue. Cetac. 

 252. 



Delphinus Shavvensis, Blainv. Jour. Phys. Desm. 

 Diet. H. Nat. ix. 153, from spec, in Mus. Col. Sury. 



D. rostratus, Shaw, 514, from same specimen. 



Blackish lead-colour, rather paler beneath. 



Inhab. India, Ganges. Skull and specimen, British 

 Museum. 



As the animal increases in age, the ends of the jaws 

 become more turned up, and the teeth enlarge and become 

 thicker at the base. 



e. Skull with the maxillary bones simple, expanded over 

 the orbit. Teeth conical. Paddles ovate or oblony. 

 Iniana. 



Synopsis of the Genera. 



1. Inia. — Teeth rugose, the hinder ones with a rounder 

 tubercle on the inner side. 



2. PoNTOPORiA. — ■ Teeth cylindrical, conical, acute, 

 curved. 



Inia, D'Orbigny. Delphinus, Desm. Delphinorhynchus, 



F. Cuv. 



Head rounded, convex. Nose produced, nearly 

 cylindrical, hairy. Blowers oblique, nearly above the 

 pectoral fins. Ear-hole distinct. Teeth numerous, ru- 

 gose, grooved, permanent ; the front, hooked ; the hinder, 

 close at the base, with a large rounded tubercle on the 

 inner side. Dorsal fin none. I3ack keeled, sub-triangular 

 behind. Body compressed behind. Pectoral fin large. 

 The skull depressed, with the nose twice as long as the 

 brain-cavity, compressed, with a groove along each side. 

 Temporal cavity very large, edged above by a strong 

 crest, and the orbital hole very short, roundish. Muzzle 

 of the young hairy. 



The Inia. Inia GeofTroyii. 



Delphinus Geoifroyii, Desm. Mam. 512. 



D. Geoffroyensis, Blainv. Desm. N.Dict. H. A^. ix. 151. 



" D. a bee mince," Cuvier, Desm. 



Delphinorhynchus frontatiis, F. Cuv. Cetac. 121. 



Inia Boliviensis, D'Orbiyny, N. Ann. Mus. vii. t. 22, f. 

 3; cop. /'. Cuv. Cetac. lO'O, t. 10*, t. 11. 



Pale blue, reddish beneath ; fins and tail olive, some 

 reddish, others blacker ; teeth 4I"tt- 



Inhab. Upper Peru or Bolino, River Moxos. Animal 

 and skull Mus. Paris. 



Length, entire, 1 met. 4 centini. 



„ of muzzle, 23 



„ to eye, 34 



„ to blower, 40 



„ to ears, 43 



„ to pectoral fin, 52 



„ to dorsal fin, 1 met. 30 



„ ofjjecloral, 42 



Breadth of pectoral, 18 



„ of caudal, 50 



Height of dorsal, 9 



Circumference of thickest part, 1 met. 4 



The specimen in the Paris Museum, which Desraarest 

 described as Delphinus Geoffroyii, is evidently this spe- 

 cies. It was taken from the Lisbon Museum, and is co- 

 vered with paint. It has no dorsal, and it shows the teeth 

 sufficiently to exhibit their rugose state, and the large and 

 peculiar tubercle on the inner side of the hinder ones, 

 which is characteristic of this genus, and which appear to 

 have been overlooked by M. Desmarest, who describes 

 them as " couique, obtuse, avec une sort de collet inferieure- 

 ment et entre leur surface est rugueuse." 



The skull in the Paris Museum from M. D'Orbigny, has a 

 prominent tubercle behind the blowholes ; eyebrows con- 

 vex and rugose on the top ; beak with a slight groove on 

 each side above ; lower jaw with scarcely any ridge on 

 the sides ; the sj'mphysis long, occupying more than 5- the 

 length of the lower jaw ; teeth large, regidar, hinder ones 

 with a rounded, regular tubercle on the inner side. 



Length of skull .... 19-0 



„ beak .... 120 



„ symphysis .... 9'0 



„ teeth line .... IPO 



Canadian Dolphin. Inia Canadensis. 



Tab. 5. Animal. 



Delphinus Canadensis, Desm. Mam. 516. 



Dauphin blanc du Canada, Duham. Pesch, ii. x. t. 10, 

 /. 4. 



Inhab. Canada. 



Dr. Richardson informs me he has seen many pure white 

 dolphins as high as Quebec, on the St. Lawrence, and he 

 has also seen a white doljihin, about 6 feet long, in Hud- 

 son's Bay ; the latter was probably a Beluga. 



M. Dc Blainville accidentally purchased in Paris the 



N 



