10 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127, 



D. H. Dunkle. Referred specimen: No. I.G.M. 52-139, Instituto 

 de Geologia de la Universidad Nacional Autonoma de Mexico ; tooth- 

 bearing right maxillary and associated parts of a macerated skull, 

 collected in October 1952 by D. H. Dunkle. 



Horizon and locality. — Sandy, nodular masses in red conglomerate, 

 respectively, 2,200 and 2,000 meters south of the town of Marfil, 

 Guanajuato, Mexico. 



Fig. 3. — Paradipsosaurus mexicanus, new genus and species (U.S.N.M. 

 No. 20667). A somewhat restored diagram of the skull in dorsal aspect. Ap- 

 proximately X 3- 



Abbreviations: j, frontal; jp, pineal foramen; j, jugal; la, lachrymal; mx, 

 maxillary; na, nasal; 0, orbit; p. parietal; pj, prefrontal; pmx, premaxillary ; 

 po, postorbital ; ptf, postfrontal ; stf, supratemporal fossa. 



Description. — The type skull, which serves as the principal basis 

 for the following description, is only slightly deformed and except 

 for the missing parts noted in its designation above, is exceptionally 

 well preserved. The appearance of the whole cranial complex and 

 the relationships of its component parts are typically lacertilian (illus- 

 trated in figs. 3-5). 



In dorsal aspect the skull is roughly triangular in outline with 

 bluntly rounded snout and with the greatest observable width occur- 

 ring in a transverse plane through the posterior halves of the orbits. 



