476 



TITANOTHERES OF ANCIENT WYOMING, DAKOTA, AND NEBRASKA 



The Brontops-Diploclonus phylum as represented in the Hatcher collection of 60 sTculls and jaws from the Chadron 

 formation, in the United States National Museum — Continued 



8316 



7749 

 7642 

 4944 

 4942 

 4939 

 8742 

 8746 

 8725 



8748 



4290 

 8792 

 8769 



8796 



4948 

 1241 



8319 



8779 

 8784 

 8785 



8764 



4258 ] 

 8776 



1233 



1235 



4259 

 4274 



4261 



8738 

 8754 



8739 



4940 



4947 

 8750 

 1214 

 1237 

 4246 

 8320 

 8782 



1862 



Female 



(?) 



(?) 



Female 



(?) 



Male 



Female 



Male 



Female 



Male- 



Male- 

 (?)-- 

 (?) — 



Female- 



Male,-. 

 Female - 



Female- 



(?) 



Female - 

 (?) 



Male--. 

 Female - 



Male- 

 (?)-.. 



Male- 



Female. 



Male. 

 Male. 



Male- 

 Male- 

 Male- 



Male- 



Female. 



Genus and species 



Brontops dispar Marsh 

 do 



-do. 

 -do. 

 -do. 



.do. 

 .do- 

 .do. 

 .do. 



.do- 



Brontops? dispar Marsh. 

 Brontops? 



Female 



(?) 



Male 



(?) Female 



Male 



(?) 



(?) 



(?)- 



Brontops (brachycephalus) dispar Marsh. 



Brontops dispar Marsh. 

 do 



.do- 

 .do- 



.do. 

 -do. 



.do. 

 .do- 



Brontops brachycephalus Osborn 



Brontops (?dispar) brachycephalus Os- 

 born. 



Brontops (brachycephalus) ?dispar 

 Marsh. 



Brontops (dispar) ?brachycephalus Os- 

 born. 



Brontops brachycephalus Osborn 



do 



Skull 



Skull 



Broken skuU 



SkuU 



Skull 



SkuU 



SkuU 



SkuU 



SkuU (part of skele- 

 ton). 

 SkuU, anterior half, 

 and jaws attached. 



Skull 



Pair of lower jaws 



Posterior part of 



skuU. 

 Right ramus and 

 symphysis. 



Lower jaws 



SkuU E, right jaw in 



matrix. 

 Lower jaws. Young 

 Pair of lower jaws.. 

 Pair of lower jaws.. 

 Right ramus, ?AUops 



marshi. 

 Pair of lower jaws.. 

 SkuU 



SkuU 



Pair of lower jaws- 



Large female (?) of progressive size. 



Canines lacking; measurements agree well. 



Equals Allops marshi? 



Medium size, adult. 



Measurements typical of female (rare) . 



Vigorous male. Teeth poorly preserved. 



Badly preserved and crushed. 



Vigorous male; young, m' just coming in; 

 medium to small size. 



.do- 

 .do- 

 -do. 



.do- 



.do- 



Lower jaw 



Pair of lower jaws- 



SkuU. 

 SkuU. 



SkuU 



SkuU 



Upper dentition. 



Skull, lower jaws, 



and femur. 

 SkuU 



.do- 



.do- 

 .do. 

 .do. 



Brontops? brachycephalus Osborn . 

 do 



Brontops brachycephalus Osborn . 



SkuU 



Upper dentition 



SkuU 



Lower jaw 



Lower jaw 



Lower jaws 



Anterior half of lower 



jaw. 

 Imperfect skuU 



Very fine female. Transitional in meas- 

 urements from B. brachycepha us to B. 

 dispar. 



Advanced stage, approaching B. dispar. 



Advanced stage, approaching B. dispar. 



Measurements agree p ecisely. Advanced 

 stage, approaching B. dispar. 



Type specimen. 



Measurements typical. 



Superior dentition of both sides; advanced 

 in size. 



Vigorous male skull; measurements typi- 

 cal. 



Canine alveoli small; molars inferior to 

 type of B. brachycephalus. 



Paratype. 



Dentition of smaUer dimensions. 



Juvenile, imperfect. 



Measurements agree closely with B. 

 brachycephalus. 



