O. C. Marsh—On Dinosaurian Reptiles. 497 
: oo : 
Genera Stegosaurus (Hypsirhophus), Diracodon, ? Dystro- 
pheus, Palewoscincus, Priconodon, all from North America ; 
and in Europe Omosaurus, Owen. Jurassic and Cretaceous. 
(2) Family Scelidosauride. Astragalus not codssified with 
tibia; metatarsals elongated ; three functional digits in pes. 
Genera Scelidosaurus, Acanthopholis, Hylewosaurus, Pola- 
canthus. Jurassic and Cretaceous. Known forms all Euro- 
pean. (Plate X, figure 6.) 
(3) Family Wodosauridw. Heavy dermal armor. Bones 
solid. Fore limbs large ; feet ungulate. 
Genus Wodosaurus. . Cretaceous, North America. 
Suborder CERATOPSIA (Horned face). 
(4) Family Ceratopside. Premaxillaries edentulous; teeth 
with two distinct roots; skull surmounted by massive horn- 
cores ; arostral bone, forming a sharp, cutting beak ; expanded 
parietal crest, with marginal armature ;? a pinealforamen. Ver- 
tebree solid; anterior cervical vertebra codssified with each 
other ; posterior dorsal vertebree supporting on the diapophysis 
both the head and tubercle of the rib; lumbar vertebree want- 
ing; sacral vertebrae with both diapophyses and ribs. Pubes 
projecting in front, with distal end expanded ; postpubic bone 
rudimentary or wanting. Limb bones solid; fore limbs large ; 
femur longer than tibia; feet ungulate; locomotion quadrupedal. 
Genera Ceratops, Agathaumas, Monoclonius, Polyonax, 
Sterrholophus, Torosaurus, Triceratops, in North America; 
and in Europe Struthiosaurus (Cratwomus). All are Creta- 
ceous. (Plate X, figure 10.) 
Suborder ORNITHOPODA (Bird foot). 
Premaxillaries edentulous in front. Vertebree solid. Fore 
limbs smal]. Pubes projecting free in front ; postpubis present. 
Feet digitigrade; three to five functional digits in manus and 
three to four in pes; locomotion mainly bipedal. 
(5) Family Oamptosauride (Camptonotide). Premaxilla- 
ries edentulous; teeth in single row; a supra-orbital fossa. 
Anterior vertebree opisthoccelian; sacral vertebrae with peg 
and notch articulation. Limb bones hollow; fore limbs small. 
Postpubis reaching to the distal end of ischium. Femur longer 
than tibia, and with pendent fourth trochanter; hind feet with 
four digits. (Plate X, figure 7.) 
Genus Camptosaurus (Camptonotus). Jurassic, North 
America. 
(6) Family Zaosauride. Premaxillaries edentulous; teeth 
in single row. Anterior vertebrae with plane articular faces ; 
sacral vertebrae codssified. Sternum unossified. Limb and 
