240 DINOSAURS OF NORTH AMERICA. 



Bathygnathus, and Clepsysaurus, in North America; and in Europe, 

 Palaeosaurus. Thecodontosaurus. All known forms, Triassic. 



Suborder Cceluria (Hollow tail). 



(G) Family Cceluridae. Teeth much compressed. Vertebrae and bones 

 of skeleton very hollow or pneumatic; neural canal much expanded; 

 anterior cervical vertebra? convexo-concave; remaining vertebrae bicon- 

 cave; anterior cervical ribs coossified with vertebra': pubes slender 

 and distally coossified; an interpubic bone. Femur shorter than tibia; 

 metatarsals very long and slender. (PI. VII.) 



Genera Ccelurus in North America, and Anstosucims in Europe. 

 Jurassic. 



Suborder Compsognaxha. 



(7) Family Compsoguathida?. Skull elongate, with slender jaws and 

 pointed teeth. Cervical vertebra- convexo-concave, with free ribs; 

 remaining vertebrae biconcave. Ischia with long symphysis on median 

 line. Bones very hollow; femur shorter than tibia; astragalus with 

 lung ascending process; three functional digits in nianus and in pes. 

 (PI. LXXXII.) 



Genus Compsognathus. Jurassic. Only known specimen, European. 



Suborder Ceratosauria (Horned saurians). 



(8) Family Ceratosauridffi. Horn on skull; teeth large and trenchant. 

 Cervical vertebra? plano-concave; remaining vertebra? biconcave. Ribs 

 free. Pelvic bones coossified; ilium expanded in front of acetabulum; 

 pubes slender; an interpubic bone; sacral vertebrae five; ischia slender, 

 with distal ends coossified. Limb bones hollow; mauus with four digits; 

 femur longer than tibia; astragalus with ascending process; metatar- 

 sals coossified; three digits only in pes. Osseous dermal plates. (Pis. 

 VIII-X. XIV.) 



Genus Ceratosaurus. Jurassic, North America. 



(9) Family Ornithoiniinida?. Pelvic bones coossified with each other 

 and with sacrum; ilium expanded in front of acetabulum. Limb bones 

 very hollow; fore limbs very small; digits with very long, pointed 

 claws; hind limbs of true avian type; femur longer than tibia; astrag- 

 alus with long ascending process; feet with three functional digits, 

 digitigrade and unguiculate. (PI. LVII1.) 



Geuus Oruithomimus. Cretaceous, North America. 



Suborder Hallopoda (Leaping foot). 



(10) Family Hallopida?. Vertebra? and limb bones hollow; vertebra? 

 biconcave; two vertebrae in sacrum. Acetabulum formed by ilium, 

 pubis, and ischium; pubes rod-like, projecting downward, but not coos- 

 sified distally; nopostpubis; ischia with distal ends expanded, meeting 

 below on median line. Fore limbs very small, with four digits in 



