1858.] ' HUXLEY — STAGONOLEPIS. 453 



lateral constriction and inferior excavation of their centra, partly 

 for the obliquity of the planes of their slightly concave anterior and 

 posterior articular faces. These faces, in fact, are not perpendicular 

 to the longitudinal axis of the centrum, but the anterior one looks a 

 little downwards and forwards, the posterior, upwards and backwards. 

 The neural arches were readily detached from their centra, and, 

 where a separation has taken place, the previously co-adapted sur- 

 faces of the centrum and the arch exhibit strong ridges and grooves, 

 which mutually interlocked. The edges of the posterior zygapo- 

 physes meet inferiorly above the neural canal (which is deepest in 

 the middle), forming a kind of inverted V. 



These and some other peculiarities of the vertebraB of Stagonolepis 

 are all shared by the Teleosauria, and ma}'- be readily seen in many 

 of the detached Teleosaurian vertebrae in the British Museum ; but 

 the vertebrae of the reptile under description present two remarkable 

 characters, for which I can find no exact parallel in either recent or 

 fossil Crocodilia. 



The first of these is exhibited by each of two imperfect natural casts 

 of anterior dorsal vertebrae, the strong and broad transverse processes 

 of these vertebrae being bent upwards and backwards at an angle of 

 45° to a horizontal or vertical plane. The second peculiarity is 

 exhibited by the caudal vertebrae, whose transverse processes come 

 off altogether above the neuro- central suture, whereas ordinarily 

 they are, as it were, wedged into this suture, and separate the cen- 

 trum more or less completely from its neural arch. 



With regard to the first of the special characters here noted, it 

 may be observed that the anterior dorsal vertebrae of different spe- 

 cies of modem Crocodilia vary a good deal in the extent to which 

 they incline upwards and backwards, and those of some Enaliosauria 

 suffer a still more marked deflexion in the same direction ; but it is 

 among the Dinosaurian reptiles that the transverse processes of 

 the dorsal vertebrae take a direction most nearly corresponding to 

 that which obtains in Stagonolepis. Without attaching too much 

 weight to this circumstance, it will be seen by and by that it is 

 worth while to bear it in mind. 



The second peculiarity to which I have directed attention may 

 perhaps be the result of the early anchylosis of the caudal trans- 

 verse processes with the neural arches. However this may be, the 

 character in question is a very exceptional one, and long led me to 

 hesitate in regarding the vertebrae in question as really caudal. 



The gradual divergence from the strictly Crocodilian type of orga- 

 nization which is manifest in the remains to which I have just 

 adverted reaches its climax in the next part I have to mention*. 

 A fragment of bone protruding from the surface of one of the blocks 

 of sandstone from Lossiemouth was the last to attract my attention 

 of all the fossils which have been sent from Elgin. Certain indica- 

 tions convinced me that, notwithstanding the extreme fragility of 

 the bony substance and the depth to which it seemed to penetrate 



* See the final Note, p. 459. 



