1891.] HELODERMA HORRIDUM AND H. SUSPECTUM. 115 



may be likewise objected to on the ground that it is not expressive 

 of the position assumed by the element in a great number of Reptiles. 



Fig. 5. 



Three posterior dorsal and tbree anterior caudal Yertebne of Heloderma sus- 

 pectum, (^ (a) and § (b), and H. horridum, $ (c) ; nat. size. 



I therefore think it best to retain the name hypapophysis (Owen), of 

 which intercentrum (Cope) becomes a synonym. 



Turning back again, after this somewhat lengthy digression, to the 



tioned that the zygosphenal articulation of the vertebrse exists in Ticpinambis 

 and Teius as in most Iguanidce. Owen was mistaken in denying tlie existence 

 of the zygosphene in AmUyrhynchus, where it is present as in most Iguanoids, 

 including Fhrynosoma and Basiliscus ; only two Iguanoid genera are known to 

 me to lack this additional articulation, viz., Anolis and Polychrus. 



It appears to me very probable that the Lizards from the Eocene of Wyom- 

 ing, described by Marsh (Am. Journ. (.3) iv. 1872, p. 299) under the name of 

 Thiiwsaiirus, as having vertebrse resembling those of Varanus, but with zygo- 

 splienal articulation, belong to the family TeiidcB, and tliere can be no shadow 

 of a doubt that the Cretaceous (Neocomian) Hydrosaunts lesincnsis of Korn- 

 huber (Abh. geol. Eeichsanst. v. 1873, H. 4, pi. xx.), placed by Zittel in the 

 Varanidcs, belongs to the Boliohosauridm, possibly to the genus Bolichosaurus 

 proper. 



8* 



