THE STRUCTURE OF MACRAUCHENIA. 321 " 



** If," say3 Professor Burmeister, " we divide the Ungulate 

 " animals according to the structure of their feet into Artiodactyles 

 " and Perissodactyles, there can be no doubt that the Euminants 

 " must form one end of the series, and the Elephants (Proloscidea) 

 *' the other. In this way we get a natural series, beginning with 

 *' the Euminants, and passing through Anoplotlierium to the Swine 

 " {Sumd) and so to Hippopotamus j which concludes the series of 

 " Artiodactyles. The transition to the Perissodactyles is, perhaps, 

 " effected by Toxodon, of which the structure of the feet is not yet 

 " accurately known, but which seems to unite certain characters of 

 " Mhinoceros with those of Hippopotamus. To Toxodon succeed 

 " Mhinoceros ^Hyr ax 2XL^JBal(B0therium — genera, of which the dentition 

 " is reducible to one common plan. Next, however unnatural it 

 " may at first appear, we must place the Solidungula — the fossil 

 " genus Hipparion, forming the transition between Eq^uus and 

 " PalceotTieriumy and, on the other side, comes in MacraucJiema, 

 " perhaps along with JVesodon. To Macrauchenia succeeds Tapirus; 

 " and the series is closed by MepJias.'^ 



It will be observed, therefore, that Prof Burmeister considers 

 that the true position of Macrauclienia is now definitely settled to 

 be between ^quus and Tapirus^ and that the resemblance to the 

 Camelidae, indicated by its cervical vertebrae, is entirely analogical, 

 and unsupported by any other characters. He defines the genus 

 as follows : — 



Macrauchenia^ genus Ungulatorum imparidigitorum, inter genera 

 Equus et Tapirus ponendum — Dentes 46, serie continua* — Pri- 

 mores utrinque sex — Laniarii parvi, conici, inferiores majores. 

 Molares supra utrinque octo ; anteriores compressi, posteriores qua- 

 drati : infra septem bilunati — Nasus elongatus, proboscideus. Cra- 

 nium figura cranio Caballi proximum — Palmse et plantsB tridactylse, 

 digitis sequalibus ; astragalus superficie unica articulatoria subor- 

 biculari cum osse scaphoideo conjunctus ; digitis externis et internis 

 accessoriis obsoletis, sed conspicuis." 



* The dentition is formularized as follows ( Abh. N. G. z. Halle, p. 85) — 

 6 _ 1—1 8-8 



The great peculiarity, besides the large number of the teeth and the eight superior 

 molars, consists in the series being almost continuous, only one small diastema 

 occurring, between the canines and incisors in the upper jaw. In this respect Ma- 

 crauchenia approaches Anoplotheriuvu 



N.H.R.— 1865. Z 



