ORDER SAUROPTERYGIA. IO/3 



saurus is distinguished by the posterior divergence of the pterygoids, 

 and not improbably by the presence of long transverse processes to 

 the dorsal vertebrae ; both of these features being Plesiosaurian. 

 The preorbital portion of the skull is very narrow. Although the 

 members of this family have lost all traces of a notochordal canal 

 in the centra of the vertebrae, yet the ossification of these centra 

 has taken place in the same manner by means of a sheath investing 

 the notochord. 



Family Lariosaurid^e. — This family is closely allied to the 

 preceding, but the limbs approximate to those of the Plesiosauridce. 

 The skull, at least in one genus, has infraorbital vacuities on the 

 palate, and the coracoid has no notch at its glenoidal extremity. 

 The femur always remains an elongated bone, longer than the 

 epipodials and metapodials collectively ; but the humerus may be 

 comparatively short, and is more or less expanded at its distal 

 extremity ; while in Lariosaurus, although not in the other forms, 

 it has lost its foramen. The terminal phalangeals of the pes still 

 retain their claws. In Neusticosaurus it is thought that cervical 

 ribs were wanting. The type genus Lariosaurus comprises one 

 medium-sized species from the Trias of Lombardy, and according to 

 Dr Baur, has both limbs adapted for walking. The palate is un- 

 known. In Neusticosaurus, from the Lettenkohle at the base of the 

 Keuper of Wiirtemberg, Professor Seeley considers that the pectoral 

 limb had become modified into a paddle, although this conclusion 

 is not accepted by Dr Baur. It appears probable that a small 

 reptile, described from the Trias of Italy under the preoccupied 

 name of Pachypleura, is not more than specifically separable from 

 Neusticosaurus. The type species of the latter was about one foot 

 in length, and was probably of amphibious habits. 



It may be convenient to notice here two small Triassic reptiles 

 which are referred by Dr Baur to this family, although Dr Deecke 

 considers that at least the second has more affinity with the Lizards. 

 These genera are Dactylosaurus, from the Muschelkalk of Silesia, 

 and Macro?uerosaurus, from the Italian Trias ; the former being 

 almost certainly referable to this order, and perhaps not separable 

 from Neusticosaurus. In this connection it should be observed that 

 Dr Bassani considers Macro?nerosaurus to be identical with the type 

 species of Lariosaurus, and that Neusticosaurus is not generically 

 separable from the latter. Pachypleura is, however, regarded as 

 distinct from Neusticosaurus, in which case it will require a new 

 name, as the present one is preoccupied. 



Finally, it should also be mentioned that some authorities would 

 regard the two preceding families as constituting a distinct sub- 

 order — the Nothosauria — but the transition to the next family is 

 almost complete. 



