Peterson : Osteology ok Oxvdaci vlus. 443 



cranium, it may be of interest to state some observations made upon 

 a series of twelve skulls of Lama huanaco, which were taken from one 

 and the same herd of upwards of one hundred animals, at Cape Fair- 

 weather, Province of Santa Cruz, Argentine Republic, South America, 

 by Mr. J. B. Hatcher and the writer, during their explorations in that 

 country. 



The chief differences in structure and variations in position are 

 observed in the third upper premolars. In some cases this tooth on 

 one side occupies its natural position with its greatest diameter directed 

 antero-posteriorly, while the corresponding tooth on the opposite side 

 is placed transversely to the long axis of the alveolar border ;° the 

 external face thus becomes anterior, and by wear a most peculiar sharp 

 transverse crest is developed on the anterior border of the tooth. In 

 some instances the tooth on one side has two strong fangs and is nat- 

 urally placed in the alveolar border, while the opposite tooth is set 

 crosswise in the jaw and has only a single internal root, the external 

 being seemingly absorbed by pm.i. In one case the third premolar 

 is present and well developed on one side and on the other side the 

 corresponding tooth has dropped out and the alveole is entirely closed. 

 In an old individual the third upper premolar is absent on both sides 

 and the alveole on one side is entirely closed, while that of the other 

 side contains a minute root, which, to judge from its soft spongy 

 character, one would be justified in saying never carried a crown. 

 (See Figs, i and 2.) 



Another somewhat less noticeable character is the position of the 

 inferior incisors. In the majority of cases the incisors have a recum- 

 bent position while frequently an individual especially an old one will 

 be noticed with that series in an almost vertical position." 



The anterior palatine foramen and the posterior nares are quite 

 variable in different individuals. The anterior palatine foramen is 

 sometimes long and narrow and either somewhat anterior to the lat- 

 eral incisor, directly opposite to it, or occupying a position posterior 

 to it. Again the anterior palatine foramen may be shorter and 

 broader, more oval in shape, and vary in position, with reference to 

 the lateral incisors. 



\In one case the fourth premolar has this transverse position while tlie tooth in 

 front of it occupies its natural position in the jaw. 



6 In the collection is a skull and lower jaw of an adult female with but two incisors 

 in the right mandible, while the left has the normal number. 



