24 FOSSIL REPTILIA OP THE 



column, its true position in the skeleton of the living reptile, and that the vertebras 

 anterior to it answer to those which are called cervical by Cuvier, in the existing 

 lizards which have four well-developed extremities. 



The artificial character of the ' cervical' vertebras of anatomy is more obvious in 

 the Lacertine Sauria than in most other vertebrates. Cuvier, who has assigned the 

 precise number of such vertebrae to several species of Lacertians, in his ' Table of the 

 Vertebras of Reptiles,'* does not define their characters. He merely observes that 

 " they have inferior crests like the anterior dorsal vertebrae."! 



With regard to the Monitor {Varanus) Cuvier affirms, in another work, J that the 

 "inferior crest distinguishes the cervical from the dorsal vertebras;" but he admits 

 that the first three of these dorsal vertebrae have an inferior tubercle. Proceeding 

 next to speak of the American Monitor {Monitor proper, or Tejus) he says, — " Les 

 vertebres cervicales, determinees par les fausses cotes anterieures, sont au nombre de 

 huit, c'est-a-dire qu'il y a six paires de ces fausses cotes. "§ This number of so-defined 

 cervicals is found in the Iguanians, Basiliscs, true Lizards, Geckos, Anolises, Agamians 

 and Stellios. But Cuvier admits that two if not three of the last of these cervical 

 vertebras, although their false ribs (pleurapophyses) do not reach the sternum, are 

 embraced hj the scapular arch, and concur in the formation of the chest : if these be 

 accordingly subtracted, the number of cervicals will be reduced, Cuvier says, to five. 

 In the ' Table of Vertebras' above cited, only four cervicals are allowed to the Iguana, 

 Basilisc, the banded Gecko, Anolis, Agama, and the Levantine Stellio, There is a dif- 

 ference, however, in the number assigned to some of these species in the table in the 

 'Ossemens Fossiles.'|| But all these discrepances depend on the inconsistent cha- 

 racters that hitherto have been assigned to the cervical vertebrae of Lizards. 



Recognising the artificial nature of such a group of vertebrae, I believe that their 

 character, which must needs be arbitrary, would be most easily determined, and, 

 therefore, most convenient in its application, which should be founded on the absence 

 of sternal ribs (haemapophyses) : according to which character the vertebra that first 

 was joined to the sternum by sternal ribs would be reckoned as the first " dorsal," 

 and all anterior to it as " cervical vertebrae." This arbitrary character would agree 

 with that by which the cervical vertebras are, in point of fact, defined in the human 

 subject and mammalia generally. 



In the fossil Lacertian, however, which forms the more immediate subject of this 

 description, there is no indication of a junction of the vertebral rib (pleurapophysis) by 

 a sternal rib (hasmapophysis) with a sternum (haemal spine), and I can only compare 

 the cervical region of the spine with that in existing Lacertians, in so far as relates to 



* LeQons d'Anat. Comp. i, (1835,) p. 220. f lb. p. 215. 



J Ossemens Fossiles, 4to, v, pt. ii, p. 284. § lb. p. 2S5. 



I! Tom. cit. p. 288. 



