1869.] HULKE STENEOSAURTJS ROSTRO-MINOR. 395 



of an anniilar fragment of a former fang around the fang of an 

 effective tooth, in one of the alveoli, and the protrusion of a small 

 immature tooth from a very wide alveolus demonstrate that, as 

 regards the manner of succession of its teeth, this Kimmeridge cro- 

 codile agreed with those of our day. 



Minute Structure of the Teeth. — This so agrees substantially with 

 that of living crocodiles that any description of it is superfluous. 



VertehrcB. — All the vertebrae which have as yet been brought 

 into view are amphicoehan ; both articular faces are moderately but 

 decidedly hollow. The centrum is cylindrical. Its middle is con- 

 stricted, laterally compressed, and overhung by the expanded arti- 

 cular ends, which have a nearly circular contour. In two of these 

 vertebrae the posterior articular face has a rather longer vertical 

 than transverse diameter, due, I think, to squeezing. The neurapo- 

 physes, laterally compressed and thin, are suturally attached to the 

 upper surface of the centrum in nearly its whole length, reaching, 

 however, nearer to the anterior than to the posterior margin. The 

 suture descends slightly on the side of the centrum. The neural 

 canal is indented by a median groove, deepest at its middle, as is 

 common in some crocodiles. 



One of the vertebrae, imbedded in the same mass of stone as the 

 ramus of the lower jaw in the British Museum, has a costal facet 

 on the anterior margin of the transverse process (diapophysis), near 

 its root, and none on the centrum, which makes it correspond to 

 the fifth or sixth thoracic vertebra of living crocodiles, from which, 

 however, it differs in the absence of a hypapophysis, as well as in 

 its hollow articular faces. Beyond this costal facet the process 

 has been unfortunately broken off ; its section is trihedral ; but the 

 right transverse process is 3-5 inches long. The posterior border of 

 the neural spine, the only part of it visible, is '5 inch thick, and 2-5 

 inches long, and it ends abruptly as if squarely truncated. The 

 postzygapophyses are very mutilated, they project backwards from 

 the neurapophysis, their lower ends nearly meeting in the level of 

 the crown of the neural canal, and their upper ends diverging. Their 

 surfaces look outwards and downwards. In another vertebral arch 

 with the spine and transverse processes, which, from the great 

 length of these latter, together with the absence of a costal facet 

 from their anterior margin, I presume to be part of a posterior 

 thoracic vertebra, the prezygapophyses project from the front of the 

 neurapophyses just above the plane of the anterior margin of the 

 diapophyses. The size and form of their surface are hidden ; but 

 their anterior margin is part of a very wide curve, and it has a 

 more nearly upward direction than in the more anterior vertebra. 



VOL. XXV. PART I. 2 E 



