THE SUBCLASS SYNAPTOSAURIA 247 



A. Suborder Nothosauria 



Crawling or swimming reptiles from three to seven feet in length, 

 of exclusively Triassic age. Skull depressed, more or less elongate, 

 the orbits situated far forward, looking upward. Nares about mid- 

 way between the orbits and extremity. Lacrimals possibly absent. 

 Palate without openings, except the large internal nares, the vomers 

 and pterygoids meeting in the middle line throughout. From twenty 

 to twenty-five cervical, twenty-five to thirty dorsal, two to five 

 sacral, vertebrae, and a moderately long tail. Clavicles stout, the 

 interclavicle vestigial. The elongated coracoids meet in the middle 

 line. Epipodials much shorter than propodials. Phalangeal formula 

 primitive, or with the loss of one phalanx in the fourth finger. Digits 

 probably webbed in life. 



The Nothosauria were all aquatic in habit, but not exclusively so 

 like the plesiosaurs, the feet still retaining terrestrial characters, with 

 but minor aquatic adaptations. The parasternals, like those of the 

 Plesiosauria, are very stout, apparently also an aquatic adaptation. 

 The body was never slender, though less broad than that of the 

 plesiosaurs, and it is not probable that they were rapid swimmers. 

 They doubtless lived in the shallow waters, as do the crocodiles, com- 

 ing frequently to land, and subsisted chiefly upon fishes and inverte- 

 brates, for the capture of which their slender, curved teeth were well 

 fitted. A pecuHar parallel adaptation to that of the contemporary 

 aquatic Labyrinthodontia is seen in the forward position of the eyes 

 in the flat skull, and also in the unusually stout clavicular girdle of 

 both. 



Several famihes have been proposed, based upon minor characters 

 of the skull chiefly. For the present they may all be placed in a single 

 family, the Nothosauridae. 



Family Nothosauridae. Upper and Middle Trias. Anarosaurus 

 Dames, Cymatosauriis Fritsch, Dactylosaurus Giirich, Doliovertehra 

 Huene, Lamprosaurus Meyer, Lariosaurus Curioni, Microleptosaurus 

 Scuphos, N eusticosaurus Seeley, Nothosaurus Miinster, Parthano- 

 saurus Scuphos, Pistosaurus Meyer, Proneusticosaurus Volz, Simo- 

 saurus Meyer. 



