128 BRITISH FOSSIL REPTILES. 



vated between it and the parapophyses {p) ; it is also excavated on each side behind 

 the base of the hypapophysis, from which a progressively widening smooth ridge is 

 continued to near the posterior surface of the centrum. The interspace at the side of 

 the vertebra, between the parapophysis and diapophysis, is smaller but deeper in the 

 Crocodilus Hastingsi(B. The neurapophyses meet above the centrum in both ; but in 

 the Crocodilus Hastinf/sice they are thicker anteriorly and thinner at their posterior 

 border, and the neural canal (fig. 2, ti) is more contracted than in the Crocodilus 

 toliapicus. 



As compared with the cervical vertebra of the Crocodilus champso'ides from Sheppy, 

 the present vertebra differs in the form of the hypapophysis in a greater degree than from 

 the Crocodilus tolicqncus. Fig. 8, PI. 3 A, shows as little as does fig. 2 in the same plate, 

 the median ridge and lateral excavations of the under part of the centrum which charac- 

 terise the present vertebra of the Crocodilus HastingsioE. The Crocodilus cJiampsoides 

 resembles the Crocodilus Hastingsiai in the character of the proportion and depression 

 of that part of the side of the centrum forming the interspace between the par- 

 apophysis and diapophysis ; but the antero-posterior extent of the parapophysis is 

 relatively less in that Sheppy species. The outer surfaces of the neurapophyses in the 

 Crocodilus Hastinxjsice slope or converge towards each other from before backwards, in 

 a much greater degree than in either of the Sheppy species. I have not observed in 

 any recent Crocodile or Alligator the median ridge, continued backwards from the 

 hypapophysis and the lateral depressions, so strongly developed, as in the Crocodilus 

 Hastin(jsice. The fore part of the neurapophyses is relatively thicker in this than in the 

 recent species. The pleurapophyses pi, (figs. 1, 2), are well developed both forwards and 

 backwards, and the latter productions are expanded and excavated above for the reception 

 of the fore part of the succeeding cervical rib. The zygapophyses [z) are thicker at their 

 base, especially the hinder pair, where the base fills up the entire interval between the 

 articular surface and the base of the spine (see fig. 2). There is the usual deep exca- 

 vation at the fore and back part of the base of the spine {ns) for the insertion of the 

 interspinal ligaments. The neural spine is compressed, moderately long, straight and 

 truncate at its summit. 



Although the hypapophysis maintains its characteristic form with much constancy 

 in the homologous vertebrae of the same species of Crocodile, it varies in different 

 cervical vertebrae of the same individual in certain existing species. It is, for example, 

 shorter and thicker in the third and fourth vertebrae than in the succeeding ones in the 

 Crocodilus acufus ; whilst in the Crocodilus hiporcatus the hypapophysis of the third 

 cervical is more compressed than that of the sixth. The greatest difference is, how- 

 ever, presented, as far as I have yet made the comparison, by the cervical vertebrae of 

 the Alliffcttor lucius, in respect of the hypapophysis, which is broad and short in the 

 third and fourth cervicals, but becomes long and slender in the succeeding ccrvicals. 

 The small vertebral centrum (fig. 4, PI, 1 D) i-esembles, in its broad and stunted 



