maesh.] PKEDENTATA. 243 



(2) Family Scelidosaurida?. Neural canal narrow; diapophyses of 

 dorsal vertebrae supporting head and tubercle of ribs. Astragalus not 

 coossified with tibia; metatarsals elongated; three functional digits in 

 pes. 



Genera Scelidosaurus, Acanthopholis, Hylaaosaurus, Polacanthus. 

 Jurassic and Cretaceous. Known forms, all European. (PI. LXXXIII.) 



(3) Family Nodosaurida;. Heavy dermal armor. Bones solid. Fore 

 limbs large; five digits in manus ; feet ungulate. 



Genus Nodosaurus. Cretaceous, North America. 



Suborder Ceratopsia (Horned face). 



Preniaxillaries edentulous; teeth with two distinct roots; skull sur- 

 mounted by massive horn cores ; a rostral bone, forming a sharp, cutting 

 beak; expanded parietal crest, with marginal armature; a pineal fora- 

 meu( ?). Vertebrae and limb boues solid; fore limbs large; femur longer 

 than tibia; feet ungulate; locomotion quadrupedal. Dermal armor. 



(4) Family Ceratopsidse. Anterior cervical vertebra coossified with 

 each other; posterior dorsal vertebrae supporting on the diapophysis 

 both the head and tubercle of the rib; lumbar vertebras wanting; 

 sacral vertebra? with both diapophyses and ribs. Neural canal in sacrum 

 without marked enlargement. Pubes projecting iu front, with distal end 

 expanded ; postpubic bone rudimentary or wanting. (Pis. LIX-LXXI.) 



Geuera Ceratops, Agathaumas, Monoclonius, Polyonax, Sterrholo- 

 phus, Torosaurus, Triceratops, in Xorth America; and iu Europe, Stru- 

 thiosaurus (Cratseomus). All are Cretaceous. 



Suborder Ornithopoda (Bird foot). 



Skull without horns ; jireinaxillaries edentulous in front. Vertebra? 

 solid. Fore limbs small. Pubes projecting free iu front; postpubis 

 present. Astragalus closely fitting to end of tibia; feet digitigrade; 

 three to five functional digits in mauus and three to four in pes ; loco.- 

 motion mainly bipedal. Xo dermal armor. 



(5) Family Camptosauridse (Camptonotidse). Premaxillaries edentu- 

 lous; teeth in single row; a supraorbital fossa. Anterior vertebrae 

 opisthocoelian ; sacral vertebra? five, not coossified, with peg-and-notch 

 articulation. Sternum unossified. Limb boues hollow; fore limbs 

 small; five digits in manus. Postpubis reaching to the distal end of 

 ischium. Femur longer than tibia, and with pendent fourth trochan- 

 ter: hind feet with three functional digits. (Pis. LIII-LVI.) 



Genus Camptosaurus (Camptonotus). Jurassic, Xorth America. 



(6) Family Laosaurida?. Premaxillaries edentulous; teeth in single 

 row. Anterior vertebras with plane articular faces; sacral vertebra? 

 coossified. Sternum uuossifled. Postpubis reaching to distal end of 

 ischium. Limb and foot bones hollow ; fore limbs very small; five digits 

 in manus; femur shorter than tibia; metatarsals elongate; four digits 

 in pes. (Pis. LV and LVII.) 



