910 REPORT— 1898. 



Order Sauropoda. 



External nares at top of skull ; premaxillary bones witli teeth ; crowns of 

 teeth rugose and more or less spoon-shaped ; large antorbital openings ; no pineal 

 foramen ; alisphenoid bones ; brain-case ossified ; no coUumellae ; postoccipital 

 bones ; no predentary bone ; dentary without coronoid process. Cervical ribs 

 co-ossified with vertebrae ; anterior vertebrae opisthoccelian, with neural spines 

 bifid ; posterior trunk vertebrae united by diplosphenal articulation ; presacral ver- 

 tebrae hollow ; each sacral vertebra supports its own sacral rib, or transverse pro- 

 cess ; no diapophyses on sacral vertebrae ; neural canal much expanded in sacrum ; 

 first caudal vertebra bi-convex ; anterior caudals proccelian. Sternal bones parial; 

 sternal ribs ossified. Ilium expanded in front of acetabulum ; pubes projecting in 

 front and united distally by cartilage ; no postpubis. Limb bones solid ; fore and 

 hind limbs nearly equal ; metacarpals longer than metatarsals ; femur longer than 

 tibia ; astragalus and calcaneum not fitted to end of tibia ; feet plantigrade, un- 

 gulate ; five digits in manus and pes ; second row of carpal and tarsal bones un- 

 ossified ; locomotion quadrupedal. 



(1) Family Atlantosauridce. A pituitary canal ; large fossa for nasal gland. 

 Distal end of scapula not expanded ; coracoid quadrilateral. Sacrum hollow ; ischia 

 directed downward, with expanded extremities meeting on median line. Anterior 

 caudal vertebrae with lateral cavities ; remaining caudals solid ; chevrons single. 



Genera Atlantosaurus, Apatosaurus, Brontosaurus. Include the largest known 

 land animals. Jurassic, North America 



(2) Family Diplodocidce. External nares at apex of skull ; no depression for 

 nasal gland ; two antorbital openings ; large pituitary fossa ; dentition weak, and 

 in front of jaws only ; brain inclined backward ; dentary bone narrow in front. 

 Scapula with shaft somewhat enlarged at summit. Ischia with shaft expanded 

 distally, directed downward and backward, with sides meeting on median lines. 

 Sacrum hollow, with three co-ossified vertebrte. Anterior caudal vertebrae pro- 

 ccelian, with sides deeply excavated, and chevrons single ; median caudals exca- 

 vated below, with chevrons double, having both anterior and posterior branches ; 

 distal caudals elongate, with rod-like chevrons. 



Genera Diplodocus and Barosawus. Jurassic, North America. 



(.3) Y?imi\j Morosauridee. External nares anterior; large fossa for nasal gland ; 

 small pituitary fossa ; dentary bone massive in front ; teeth very large. Shaft of 

 scapula expanded at distal end; coracoid suboval. Sacral vertebrae four in number, 

 and nearly solid ; ischia slender, with twisted shaft directed backward, and sides 

 meeting on median line. Anterior caudals solid ; chevrons single. 



Genera Morosaurus, Camarasaurus (?) (Amphiccelias). Jurassic, North 

 America and Europe. 



(4) Family Pleuroccelidcs. Dentary bone constricted medially; teeth with 

 crowns like those of Diplodocus. Cervical vertebrae elongate ; centra hollow, with 

 large lateral openings ; sacral vertebrae solid, with lateral depressions in centra ; 

 caudal vertebrae solid ; anterior caudals with fiat articular faces, and transversely 

 compressed neural spines ; median caudal vertebrae with neural arch on front half 

 of centrum. Ischia with compressed distal ends, and sides meeting on median 

 line. 



Genera Pleurocoelus, Astrodon (?). Jurassic, North America and Europe. 

 Include the smallest known Sauropoda. 



(5) Family Cardiodontidce. Teeth of moderate size. Upper end of scapula 

 expanded; humerus elongate; fore limbs nearly equalling hind limbs in length. 

 Sacrum solid ; ischia with wide distal ends and sides meeting on median line. 

 Caudal vertebrae biconcave ; median caudals with double chevrons. 



Genera Cardiodon (Oetiosaurus), Bothriospondylus, Ornithopsis, and Peloro- 

 saurits. European, and probably all Jurassic. 



(6) Family Titanosauridce. Fore limbs elongate; coracoid quadrilateral. 

 Presacral vertebrae opisthoccelian ; first caudal vertebrae biconvex ; remaining 

 caudals proccelian ; chevrons open above. 



Genera Titanosaurics and Argyrosaurus. Cretaceous (?), India and Patagonia. 



