34 FOSSIL REPTILIA OF THE LONDON CLAY. 



Vertebra of the Crocodilus toliapicus, Tab. IV and Tab. V, fig. 1, 2, 3, 5, 6. 



The vertebra, fig. 1, 2, T. V, is the fourth cervical ; it differs from that of the 

 Crocodilus acutus, Croc. Suclius, and Croc, biporcatus, in the greater breadth and squareness 

 of the base of the hypapophysis (fig. 2 k), which extends almost to the bases of the 

 parapophyses p ; the vertical diameter of the parapophyses is greater in comparison with 

 their antero-posterior extent in the fossil tban in the above-cited recent Crocodiles ; 

 the neurapophyses are thicker, and terminate in a more rounded border both before 

 and behind ; their bases extend inwards, and meet above the centrum, whilst a narrow 

 groove divides them in the recent Crocodiles above cited ; the length of the centrum 

 is greater in proportion to the height and breadth in the fossil vertebra. In other 

 respects the correspondence is very close, and the modem crocodilian characters are 

 closely repeated. Traces of the suture between the centrum and neurapophysis remain, 

 as shown at n, n, fig. 1 . The diapophysis d, and the upper portion of the neural arch, 

 with the zygapophyses and neural spine, have been broken away ; the borders of the 

 articular ends of the centrum have been worn away. 



The vertebra (fig. 3, T. V) is the sixth cervical : in this specimen the base of the 

 hypapophysis is contracted laterally and extended antero-posteriorly ; the side of the 

 centrum above the parapophysis (p) has become less concave ; the vertebra has increased 

 more in thickness than in length ; in these changes it corresponds with the modern 

 Crocodiles ; it has been mutilated and worn in almost the same manner and degree as 

 the fourth cervical. 



The vertebra (fig. 1, 2, T. IV) is a seventh cervical of a smaller individual of the 

 Crocodilus toliapicus. The lrypapophysis has become more compressed and more 

 extended antero-posteriorly ; the parapophysis has become shortened antero-posteriorly, 

 and increased in vertical diameter. The anterior concave surface of the centrum 

 (fig. 1) is more circular, less extended transversely, than in the corresponding vertebra 

 of the recent Crocodiles compared with the fossil. 



Fig. 3, 4, T. IV, are two views of the eighth cervical of an individual of about 

 the same size as that to which the fourth and sixth cervicals in T. V belong. Fig. 4, 

 exemplifies the same difference which fig. 1 presents in regard to the more circular 

 contour of the anterior concave surface of the centrum as compared with recent 

 Crocodiles ; the bases of the neurapophyses are thicker and more rounded anteriorly ; 

 the neural canal is rather more contracted ; the base of the hypapophysis more extended 

 in the axis of the vertebra (see fig. 3) than in the recent Crocodiles compared. The 

 parapophyses have now risen, as in those Crocodiles, to the suture of the neurapophysis, 

 and the diapophysis springs out at some distance above that suture. 



Fig. 6, T. IV, shows the under surface of a dorsal vertebra, in which the 

 hypapophysis ceases to be developed (probably the fourth or fifth). 



Fig. 5, T. IV, gives the same view of one of the lumbar vertebras, showing the 



