CRETACEOUS. FORMATIONS. Ill 



sides, however, are separated below by a broader quadrate tract which is slightly 

 concave transversely, and more so lengthwise, with each of its angles developed into 

 an articular hypapophysis, y y, for the junction of a portion of the base of a haemal 

 arch. This part, which is shown in T. XXXIII and XXXIV, near the middle of the 

 upper border of the slab, consists, as usual, of a pair of " heemapophyses," but they are 

 confluent with one another, not only where they form the base of the long haemal spine, 

 but also at their opposite extremities ; and the hinder hypapophysial surfaces, y y,' 

 which are the largest, also run into one another across the middle line. The articular 

 end of the centrum, fig. 2 c, presents something between a quadrate and an elliptical 

 form, with the long axis vertical ; it is a little depressed within the border. The 

 neural arch is anchylosed to the centrum ; a rudiment of a parapophysis appears at 

 the side of its base ; the diapophysis rises above and behind this, and extends 

 obliquely upwards, outwards, and backwards ; its extremity is broken off. The 

 zygapophyses, z g, figs. 1 and 2, are reduced to short tuberosities, without articular 

 surfaces in this region of the spine ; and the neural platform and its buttresses are 

 quite suppressed. The summit of the neural spine is broken away. 



Amongst the portions of ribs that are preserved, some show clearly not only the 

 head but the neck and an articular tubercle ; superadditions, which at once remove the 

 Iyuanodon from the Iguana and all its Lacertian congeners, and show the nearer affinity 

 of the great Dinosaur to the Crocodiles ; in one of the specimens near the upper part 

 of the slab, as figured in T. XXXIII, there is an indication of the upper part of the 

 neck of the rib rising and bifurcating near the tubercle, whence it is continued as two 

 ridges which form an anterior and posterior margin, as it were produced and overhanging 

 the body of the rib. This character may not be without its value in detecting and 

 determining fragments of ribs, which are common among the fossils of the strata 

 containing the remains of great reptiles. 



Both the bones, answering to those from the Wealden of Tilgate, which Cuvier 

 thought " might be a clavicle,"* are preserved in the Maidstone specimen, having 

 the same long, slender, triedral shaft slightly expanded, flattened and bent at one 

 extremity ; more expanded, flattened, and bent at an open angle at the opposite end ; 

 with a short pointed process sent off at the angle, and a broad subquadrate flattened 

 plate projecting from the same border of the bent and expanded end, which has a 

 truncate termination. In the Cyclodus\ lizard I find the clavicle is bent at an open 

 angle, but nearer its middle part ; and the difference between this and the nearly 



* Quoted by Dr. Mantell, in ' Geology of the Soutli-East of England,' 1833, p. SOS. 



f This is the Lizard referred to in the following passage of Dr. Mantell' s Paper, in the 'Philosophical 

 Transactions,' 1841, p. 138. "In a very small Lizard in the Hunterian Museum, Mr. Owex pointed out 

 to me a bone attached to the coracoid and omoplate, that bore some analogy to the one in question :" 

 it bears sufficient analogy to support the conclusion in the test, but lends no countenance whatever to the 

 idea of the fossil in question being a peculiar superaddition to the Saurian skeleton, requiring a new name. 

 The "os Cuvieri" is, in fact, abandoned in the Paper, in the 'Phil. Trans.,' 1849. 



