1891.] 



HELODERMA HORRIDTJM 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 three anterior caudal vertebra; of Rdodcriaa sus- 

 pectitm, c? («) and $ (i), and H. horndum, $ (c) ; nat. size. 



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

 which intercentrum (Cope) becomes a synonym. 



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



tioned that the zygosphenal articiUation of the yertebriB exists in Tupinambis 

 and Teius as in most Iguo,nid<e. Owen was mistaken in denj-ing the existence 

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

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

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



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 

 Tkinosaiirus, as having vertebrae resembling those of Varanus, but with zygo- 

 splnenal articulation, belong to the family Teiide, and there can be no shadow 

 of a doubt that the Cretaceous (Neocomian) Hydrosaurus lesinensis of Korn- 

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

 VaranidcB, belongs to the Dolickosauridce, possibly to the genus Dolichosaurus 

 proper. 



8* 



