camelid^;. 147 



40568. Part of the left ramus of the mandible, showing the last 

 four cheek-teeth ( m . 3 imperfect) in an early stage of 

 wear. The teeth correspond in size with those of the last 

 specimen, the length of the base of the crown of m. 2 being 

 0,033. This tooth shows the characteristic median hollow 

 at the base and the ridge at the summit of the inner sur- 

 face. The enamel is perfectly smooth. The mandible is 

 relatively slender ; but this is probably due to immaturity. 



16577. Part of the left ramus of the mandible of an immature indi- 

 vidual, showing m. 1 and m. 2 in an early stage of wear, 

 and parts of p m . 4 and m . 3 in alveolo. 



39599. Part of the right ramus of the mandible, showing the outer 

 halves of the three true molars. This specimen agrees 

 with the present species in its small size and the great 

 depth of the horizontal ramus. 



Presented by Gen. Sir W. E. Baker, K.C.B., 1848. 



Genus AUCHENIA, Illiger 1 . 



Including Lama, Cuvier 2 . 



Palauchenia, Owen 3 . 



Palceolama, P. Gervais 4 . 



(?) Hemiauchenia, H. Grervais and Ameghino 5 . 



Dentition : — In the adult living species the normal formula is 

 I. ^, C. j, Pm. |, M. I ; but pin. 3 is often absent ; the lanariform 

 pm. 1 of Camelus is the upper tooth which has disappeared. In the 

 so-called Palauchenia ( = Palceolama, teste H. Gervais) pm. 3 is always 

 present, and p~m7l exists in a specimen figured by Owen 6 . In 

 Hemiauchenia there are Pm. |. In the opinion of the present writer, 

 the mere presence of one or more additional premolars is not a 

 character of generic value, and he is therefore indisposed to accept 

 Palauchenia ; but it is hinted that there are differences in the 

 structure of the teeth of Hemiauchenia which may indicate generic 

 distinction. Further descriptions are required to determine the 



1 Prodromus, p. 103 (1811). 



2 Tableau Generale, appended to ' Lefjons d'Anatomie Comparee, 1st ed. 

 (1800). Subsequently abandoned for Auchenia. 



3 Phil. Trans. 1870, p. 65. 



4 Not found. Quoted by H. Gervais and Ameghino. 



5 Mammiferes Fossiles de l'Amerique Meridionale, p. 121 (1880). 



6 Gervais and Ameghino give the number of lower premolars in Auchenia 

 as 1, and in Palauchenia (Palceolama) 2. 



L 2 



