AVillistox.] Mosasaurs. 93 



SYSTEMATIC POSITION. 



There has been much controversy regarding the systematic 

 position of the Mosasaurs. By many they are considered to be 

 a suborder of the Squamata, coequal with the Lacertilia and 

 Ophidia, and this view has the support of Cope, Boulenger, and 

 Dollo, all eminent herpetologists. On. the other hand, Owen, 

 Marsh and Baur contend that they belong among the Lacertilia. 

 If one accepts the division of the Lacertilia into Lacertilia, 

 Khiptoglossa, and Dolichosauria, then I believe that the sub- 

 order Mosasauria should find an independent place with them. 

 But otherwise I believe that they should be included among the 

 Lacertilia in the wider sense as a distinct tribe. Surely the 

 natatory character of their limbs, and the absence of sacrum, 

 together with important differences in the skull, are sufficient to 

 entitle them to a position of their own, distinguished from all 

 other lizards. But, in any event they do not present any dis- 

 tinct relationships with the Ophidia, and the name Pythonomor- 

 pha in consequence must be given up. 



The history of the controversy between Professor Cope and 

 the various authors who have contended for the subordinate 

 position of the group is of sufficient importance to warrant a 

 brief review here, with references to the literature concerned, to 

 which the reader may turn, should he desire to pursue the sub- 

 ject further. 



Cuvier, who was the first to publish a scientific discussion of 

 the nature and structure of the Mosasaurs, contended that they 

 were nearest allied to the Monitors and Iguanas. 40 



GoldfusSj who published an excellent and extended paper on 

 an American form of the group, 41 expressed his views of their 

 relationship as follows: "The depressed, elongate form of the 

 anterior part of the head, the narrow, long nares, the structure 

 of the lower jaw and the presence of the palatal teeth, affirm 

 Cuvier's claim that this genus of animals finds its systematic 

 position between the Monitors and Iguanas. If we follow the 



40. Sur le Grand animal fossile des cariere de Maestricht, Ann. Mus. Hist. Nat., xn, 145, 1808. 



41. Der Schaedelbau des Mosasaurus, Act. Acad. Caes. Leop. Carol. Nat. Cur., xxi, 1843. 



