1835.] Scientific Intelligence. 11 



swimming paws. Behind the eye, is the meatus auditorius extemus. 

 The anterior fins are large and obtuse at their extremity. The 

 dorsal one is placed at about a third from the extremity of the tail. 

 The posterior part of the body is compressed. The tail is large and 

 divided in the middle. The cranium is depressed. The snout is 

 long and supplied with teeth throughout its whole length, and has 

 from 130 to 134 teeth. The vulva of the specimen examined was 

 much swelled. The mammae, situated on the sides of the vulva, 

 were filled with milk which was easily pressed out. It appears that 

 the males attain a greater length than the females, some of the for- 

 mer reaching a length of 4 metres (13*12 feet). This species was 

 found in all the rivers in the province of Moxos. It reaches the 

 bottom of the C'ordilleras and never appears to visit the ocean, be- 

 cause it is so slow in swimming, that it could not possibly pass the 19 

 cascades of the river Madeiras, which exist in 9" and 10° S. L. The 

 Brazilian merchants who have travelled from Mato-grossa to Para, 

 state that these dolphins are found only above the falls, that is to say, 

 in the numerous rivers comprised between 10° and 17° S. L, 



When not alarmed, these animals come quietly and much more 

 frequently, than the marine species to breathe at the surface of the 

 water, but when frightened they increase their speed, which is never 

 so rapid as that of the sea species. They generally swim in threes 

 or in pairs. Their sense of hearing seems very acute. They prey 

 upon the smaller fish, and frequently come to the surface to devour 

 their victims, which the sea dolphins never do. The Brazilians call 

 them Bote, the Spaniards Bufeo, the Guayaros Inia, the Chapa- 

 curas Sisi, the Baures Thui, the Moxos Indians A'ico^ the Itona- 

 mas Puchca, the Cayuvava Potohi. — ( Nouv, Ann. dm Museum. 

 iii. 28.) 



X. — Combinations of Iodine with Paladium and Iridium. 



The affinity of palladium for iodine is greater than that of platinum 

 for the same substance; for whenever the polished surface of the 

 palladium is brought in contact with the vapour of iodine at common 

 temperatures, or with the alcoholic solution of iodine it becomes 

 brown, which disappears by the action of ammonia or by the appli- 

 cation of heat. This affords an easy method of distinguishing the 

 two metals ; for no effi^ct is produced on platinum at a common 

 temperature. 



The best mode of preparing the iodide of palladium is to mix a 

 solution of the iodide of potassium with the salts of palladium, 

 especially the chloride of that metal. A black flocky precipitate is 

 immediately produced. When collected on a filter and washed with 

 boiling water it presents the appearance of a black gelatinous mass, 

 which in drying passes through a series of changes like alumina. 

 When fully dry it has a resinous fracture, and is easily reduced to 

 powder between the fingers. In this state it is a hydrate, but it 

 readily loses its water by being placed in a dry vacuum for twenty- 

 four hours. 



