300 THE NATURAL 7JI,ST0T?Y IlEYIEW. 



cervical vertebrsa in Mammalia, were, as is well-known, veiy few in 

 number. The only two exceptions known to Dr. Peters, were that 

 of the genus Bradypus, amongst the species of which, the cervical 

 vertebrse are either one or two more, and that of the Walrus {Tri- 

 checJius), in which the cervical vertebrse are, usually, one less than the 

 ordinary number.* To these according to Dr. Peters' investigations 

 we must now add the Two-toed Sloth of Costa Eica, which has only 

 six cervical vertebrae, and is thereby, as well as by other characters, 

 well distinguished from its southern representative Ch. dldactylus, of 

 Northern Brazil and Guiana, in which the usual number of seven 

 cervical vertebrae is found. Dr. Peters had received five skeletons of 

 this Sloth, in all of which the number of cervical vertebrae was six. 

 In four of the specimens these vertebrae were all separate ; in the fifth 

 specimen the second and third had become united as is sometimes 

 the case in Ch. didactylus, and in this example, moreover, the sixth 

 cervical had coalesced with the first dorsal vertebra. 



"We believe that the British Museum has lately acquired one of 

 these skeletons by exchange from the Eoyal Zoological Museum of 

 Berlin. 



5. MaCEATJCHENIA PATACHOyiCA. 



Letters from Prof. Burmeister, Director of the Museum of 

 Buenos Ayres, state that that distinguished Naturalist is now prin- 

 cipally engaged in investigations into the fossil Pauna of the 

 Argentine Eepublic. Prof Burmei&ter states that he has already 

 made a magnificent collection of specimens formed by different 

 collectors in several localities, and will shortly publish the first 

 number of a new Journal to be called the "Annals" of the 

 Museum of Buenos Ayres, wherein the perfect skeleton of Macrau- 

 cJtenia Patachonica (established by Professor Owen on some vertebrae 

 and other fragmentary portions of a skeleton discovered by Mr. 

 Darwin during the voyage of the Beagle) will be described. 



Dr. Burmeister' s description of this skeleton will be looked for- 

 ward to with greater interest, as it will, no doubt, settle the question 

 as to the correct classification of Macrauchenia, which its first de- 



* A third exception not noticed by Dr. Peters is that of the African Manatee 

 {Manafus senerjalens'ts), in wliich, as recorded in the last number of this Journal 

 (N. H, R. 1865, p. 18), there are certainly only six cervical vertcbroe.— Ed. 



