Prof. 0. C. Marsh — Classification of Dinosaurs. 397 



wanting ; sacral vertebras with both diapophyses and ribs. Pubes 

 projecting in front, with distal end expanded; postpubic bone rudi- 

 mentary or wanting. 



Genera Ceratops, AgatJiaumas, Monoclonius, Polyonax, Sterrko- 

 lophus, Torosaurus, Triceratops, in North America ; and in 

 Europe, Struthiosaurus (Cratceomns). All are Cretaceous. (Figure 7.) 



Sub-order Ornithopoda (Bird foot). 



Skull without horns ; premaxillaries edentulous in front. Verte- 

 bras solid. Pubes projecting free in front ; postpubis present. Fore 

 limbs small ; astragalus closely fitting to end of tibia ; feet digiti- 

 grade ; three to five functional digits in manus and three to four in 

 pes ; locomotion mainly bipedal. No dermal armour. 



(5) Family Camptosauridce (Camptonotidce) . Premaxillaries 

 edentulous ; teeth in single row ; a supra-orbital fossa. Anterior 



Fig. 8. — Camptosaurtjs dispar, Marsh. ^. Jurassic, Wyoming. 



vertebras opisthoccelian ; sacral vertebras with peg and notch articu- 

 lation. Limb bones hollow; fore limbs small; five digits in 

 manus. Postpubis reaching to the distal end of ischium. Femur 

 longer than tibia, and with pendent fourth trochanter ; hind feet 

 with four digits. (Figure 8.) 



Genus Camptosaurus (Camptonotus). Jurassic, North America. 



(6) Family Laosauridce. Premaxillaries edentulous; teeth in 

 single row. Anterior vertebras with plane articular faces ; sacral 

 vertebras coossified. Sternum unossified. Postpubis reaching to 

 distal end of ischium. Limb and foot bones hollow; fore limbs 

 very small ; five digits in manus ; femur shorter than tibia ; meta- 

 tarsals elongate ; four digits in pes. 



Genera Laosaarus and Dnjosaurus. Jurassic, North America. 

 (Figure 9.) 



(7) Family Hypsilophodontidce. Premaxillaries with teeth ; teeth 

 in single row ; sclerotic bony plates. Anterior vertebras opistho- 



