SYNOPSIS OF THE VEUTEBltATE FAUNA OF THE PUEIICO SERIES. 355 



pointed out, in the smallur tiansversc diameter of the prenioUirs, especially of 

 the superior series, and in the absence of ein^ula on the exteinal side of the 

 premolars in both jaws. The inferior true molars also possess but traces of the 

 cingula. The internal cinguluni of the superior premolars is extensive, contimiing 

 round to the front and nearly to the external base of the first premolar. In the infe- 

 rior premolars there is a short posterioi' heel, and on the first, a short anterior cingu- 

 luiu, which is however nut always present. The infraorbital i'urameu issues above the 

 front of the first premolar. 



Measurements. No. 1 t)/j)e. II. 



Length of p. m. i, m. i, and m. ii, superior 029 



( iintoroposlerior, superior Oil 



Diameters p. m. i 



I Inmsverse, " 013 



( anteroposterior 012 



Diameters p. m. u, inferior < 



(^ transverse 008 



Superior Molars, No. 2. 



Length of molar scries 070 



" " true molars 029 



{Hutcroposlcrior 010 

 transverse Oil 



^. ..(anteroposterior 098 



Diameters m. ii < 



[^ transverse 013 



Inferior Molars, No. 3. 



Length of last five molars 030 



^. . .anteroposterior 0115 



Diameters p. in. i < 



transverse 0095 



11. ii < 



„. , ... anteroposterior 008 



Diameters of m. ii •{ 



transverse 008 



„. . . ...(anteroposterior 0088 



Diameters of in. Ill ^ 



( transverse 007 



From the Lower Puerco only. I ). Baldwin. 



ECTOCONUS Cope. 

 Amer. Naturalist, 1884, p. 79.'3 ; Tertiary Vertebrata, 1885, PI. XXXV. 



But one species, the £". dilri(/onus Cope, is known. Excepting the briel" notes 

 contained in the aliovc-mentioned publications the general characters of both genus 

 and species remain undescribed. 



In the superior dentition the first, second and third premolars possess one exter- 

 nal and one internal cusps. In ili* inHiior series the first and second have an internal 

 cusp and a heel. The coracoid process is a robust lecurved tuberosity. Tlie astra- 

 galus is slightly convex anteroposteriorly, and slightly concave transversely. The 



