﻿416 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  vol. 
  103 
  

  

  Megalagus 
  brachyodon 
  (Matthew) 
  

  

  USNM 
  18903, 
  right 
  mandible 
  with 
  P4-M3; 
  USNM 
  18902, 
  right 
  

   mandible 
  with 
  P3-M2. 
  Both 
  specimens 
  are 
  from 
  locality 
  No. 
  24LC16. 
  

  

  This 
  limited 
  material 
  does 
  not 
  permit 
  any 
  additions 
  to 
  Burke's 
  

   (1936, 
  p. 
  150) 
  discussion 
  of 
  this 
  species. 
  

  

  Archaeolagus 
  sp. 
  

  

  USNM 
  19096, 
  right 
  maxillary 
  fragment 
  with 
  P*-M^ 
  from 
  locality 
  

   No. 
  24LC18. 
  

  

  This 
  specimen 
  is 
  so 
  incomplete 
  that 
  the 
  generic 
  reference 
  is 
  only 
  

   provisional. 
  The 
  teeth 
  are 
  greatly 
  flattened, 
  the 
  transverse 
  diameter 
  

   is 
  twice 
  the 
  anteroposterior. 
  The 
  hypostria 
  is 
  deep, 
  extending 
  nearly 
  

   to 
  the 
  middle 
  of 
  the 
  tooth, 
  a 
  little 
  closer 
  to 
  the 
  posterior 
  edge 
  than 
  

   the 
  anterior, 
  and 
  extending 
  to 
  the 
  base 
  of 
  the 
  tooth. 
  Groove 
  on 
  the 
  

   lateral 
  surface 
  of 
  the 
  tooth 
  shallow 
  and 
  broad. 
  No 
  crescentic 
  vaUey 
  

   (this 
  may 
  be 
  a 
  state 
  of 
  wear). 
  No 
  enamel 
  on 
  the 
  lateral 
  surface 
  of 
  the 
  

   tooth. 
  Cement 
  present 
  only 
  in 
  the 
  hypostria 
  (this 
  may 
  be 
  an 
  accident 
  

   of 
  preservation) 
  . 
  The 
  teeth 
  appear 
  to 
  be 
  rootless. 
  

  

  Order 
  CARNIVORA 
  

   Family 
  Canidae 
  

  

  Hesperocyon 
  paterculus 
  (Matthew) 
  

  

  USNM 
  18911, 
  skull 
  and 
  jaws 
  (fig. 
  48) 
  with 
  the 
  greater 
  portion 
  of 
  

   the 
  skeleton; 
  USNM 
  18897, 
  right 
  mandibular 
  fragment 
  with 
  Mi_3; 
  

   USNM 
  18896, 
  left 
  mandibular 
  fragment 
  with 
  Mi 
  4 
  2; 
  USNM 
  18895, 
  

   left 
  mandibular 
  fragment 
  with 
  P2 
  * 
  3, 
  Mi_3. 
  Specimens 
  are 
  from 
  

   locahty 
  Nos. 
  24LC16 
  and 
  24BW18. 
  

  

  Description. 
  — 
  Dental 
  formula: 
  I?, 
  C}, 
  P|, 
  M^. 
  Upper 
  dentition: 
  

   P^ 
  single 
  rooted 
  and 
  closer 
  to 
  C 
  than 
  to 
  P^; 
  P^ 
  with 
  anterior 
  cingulum. 
  

   incipient 
  posterior 
  cusp 
  and 
  minute 
  cusp 
  on 
  heel 
  ; 
  P^ 
  with 
  well 
  developed 
  

   anterior 
  cingulum, 
  posterior 
  cusp 
  and 
  a 
  cusp 
  on 
  heel; 
  P* 
  with 
  incipient 
  

   anterior 
  cusp 
  ; 
  M^ 
  without 
  incipient 
  metaconule, 
  paracone 
  higher 
  than 
  

   metacone, 
  protocone 
  well 
  developed, 
  protoconule 
  small 
  but 
  distinct, 
  

   hypocone 
  well 
  developed, 
  anterior 
  cingulum 
  terminates 
  at 
  base 
  of 
  

   protocone; 
  M^ 
  similar 
  to 
  M^ 
  but 
  smaller; 
  M' 
  minute 
  and 
  probably 
  of 
  

   no 
  systematic 
  significance. 
  Lower 
  dentition: 
  Pi 
  & 
  2 
  missing, 
  Pi 
  

   single 
  rooted 
  and 
  closer 
  to 
  C 
  than 
  to 
  P2; 
  P3 
  & 
  * 
  differ 
  only 
  in 
  size, 
  each 
  

   with 
  well-developed 
  anterior 
  basal 
  and 
  posterior 
  cusp, 
  heel 
  well 
  

   developed 
  and 
  with 
  a 
  small 
  cusp; 
  Mi 
  with 
  well-developed 
  hypoconid 
  

   and 
  incipient 
  entoconid; 
  M2 
  with 
  protoconid 
  and 
  metaconid 
  sub- 
  

   equal 
  and 
  elevated 
  above 
  the 
  paraconid, 
  hypoconid 
  well 
  developed, 
  

   entoconid 
  incipient; 
  M3 
  small, 
  protoconid 
  and 
  metaconid 
  subequal. 
  

  

  