426 PROJF. T. H. HUXLEY ON STAGONOLEPIS ROBERTS Otf I, 



is undoubtedly the Belodon of the Upper Keuper of Wiirttemberg, 

 the remains of several species of which have been well figured and 

 described by the late Hermann von Meyer*, who makes known the 

 characters of vertebrae of various regions (though none from the 

 sacrum), very perfect crania and teeth, the scapula, coracoid and 

 humerus, the ilium and the femur. Moreover, during a brief visit 

 to Stuttgart in 1873, Herr Kapff had the goodness to show me a 

 well-preserved pelvis, with the ischium in place. 



An extensive comparison can therefore be instituted between Sta~ 

 gonolepis and Belodon ; and it proves that the two genera closely re- 

 sembled one another, but, nevertheless, were separated by many 

 differential characters. For example, the teeth are totally different. 

 So far as the nasal apertures are concerned, Stagonolepis agrees 

 generally with Belodon, though the form both of the external and 

 the posterior nares was different. But there can be no doubt 

 that Stagonolepis and Belodon are members of one and the same 

 natural group, and that this group must be included among the 

 order Qrocodilia. 



The Crocodilia are defined from all other Reptilia, whether recent 

 or extinct, by the following characters : — 



The transverse processes of the majority of the cervical and 

 thoracic vertebras are divided into more or less distinct capitular and 

 tubercular portions ; and the proximal ends of the ribs which ap- 

 pertain to these vertebras are correspondingly divided into capitula 

 and tubercula. The dorsal ends of the subvertebral caudal bones 

 are not united ; the quadrate bone is fixed to the side of the skull ; 

 the pterygoid bones send forward median processes, which separate 

 the palatines, and reach the vomers. 



There is an interclavicle, but no clavicles. The ventral edge of 

 the acetabular portion of the ilium is entire, or but slightly exca- 



* " Reptilien aus dem Stuben-Sandstein des obern Keupers." — ' Palteontogra- 

 pliica,' Bande vii., x., xiv. 1861-1865. 



Professor Cope (" Synopsis of the Extinct Batrachia and Keptilia of North 

 America,"), writing in 1869, and therefore with all the materials for form- 

 ing a judgment afforded by Yon Meyer's publications, takes a very different 

 view of the affinities of Belodon from that here adopted. 



" Thecodontia (Owen). 



" In this suborder we have a singularly generalized group, combining charac- 

 ters of Lizards, Crocodiles, and Sauropterygians. The neural arch of the ver- 

 tebra?, united by suture, and the slightly biconcave centrum, resemble the last 

 two, as also the abdominal ribs. The limbs are rather Crocodilian, the position 

 of the nares Plesiosaurian. The clavicle is Lacertian, while the three vertebras 

 of the sacrum and the femur are between these and the Dinosauria. The most 

 important characters distinguishing these animals from the Sauropterygia are 

 the presence of an elongate sacrum and the more ambulatory form of the limbs. 

 Our knowledge of this order is almost confined to Belodon (Meyer), and is de-' 

 rived from that author's descriptions of three large and remarkable reptiles 

 derived from the Keuper of Wurttemberg — the Belodon Kapfii (Meyer), B. 

 Plieningeri (Miinst.), and B. planirostris (Meyer)." 



Where did Professor Cope obtain his information respecting the " clavicle " 

 and the sacrum of Belodon ? 



