498 O. C. Marsh—On Dinosaurian Reptiles. 
foot bones hollow; fore limbs very small; five digits in 
manus; femur shorter than tibia; metatarsals elongate; four 
digits in pes. 
Genera Laosaurus and Dryosaurus. Jurassic, North 
America. (Plate X, figure 4.) — 
(7) Family Hypstlophodontide. Premaxillaries with teeth ; 
teeth in single row. Anterior vertebrae opisthoccelian ; 
sacral vertebree codssified. Sternum ossified. Limb bones 
hollow; five digits in manus; femur shorter than tibia; hind 
feet with four digits. 
Genus SLypsilophodon. Wealden, England. (Plate X, 
figure 9.) 
(8) Family J/guanodontide.. Premaxillaries edentulous ; 
teeth in, single row. Anterior vertebrae opisthoccelian. 
Sternal bones ossified. Postpubis incomplete. (Plate X, 
figure 11.) 
Genera Jguanodon, Vectisaurus. Jurassic and Cretaceous. 
Known forms all European. : 
(9) Family Zrachodontide (Hadrosauride). _Premaxillaries 
edentulous; teeth in several rows, forming with use a tessel- 
lated grinding surface. Cervical vertebree opisthoccelian. 
Limb bones hollow ; fore limbs small. Femur longer than tibia. 
Genera TZrachodon (Hadrosaurus, Diclonius), Cronodon. 
Cretaceous, North America. 
(10) Family Claosauride. Premaxillaries edentulous; teeth 
in several rows, but a single row only in use. Cervical verte- 
bree opisthoccelian. Limb bones solid; fore limbs small. Ster- 
nal bones parial. Postpubis incomplete. Feet ungulate; three 
functional digits in manus and pes. (Plate X, figure 12.) 
Genus Claosaurus. Cretaceous, North America. 
(11) Family Vanosauride. Teeth compressed and pointed, 
and in asingle, uniform row. Cervical and dorsal vertebree short 
and biconcave. Limb bones and others very hollow; fore limbs 
of moderate size. Sacral vertebre three; ilium with very short 
pointed front, and narrow posterior end. Femur curved, and 
shorter than tibia; fibula pointed below; metatarsals very long 
and slender. Anterior caudals short. 
Genus WVanosaurus. Jurassic, North America. Includes 
the smallest known Dinosaurs. 
EXPLANATION OF PLATE X. 
Restorations of Dinosaurian Reptiles. 
In this plate, the scientitic name, the size, geological formation, and country 
where found, are given under each of the twelve figures. The skeletons here 
restored are represented in the same general position, to aid in comparing them 
with each other. 
This plate is a reduced copy of the chart shown at Leyden, when the present 
paper was read. The same chart was also shown at the meeting of the British 
Association, Ipswich, September 14, 1895. 
