GLIRES OF THE SANTA CRUZ BEDS. 



393 



ward ; the two glenoid cavities are almost parallel, converging forward 

 but slightly. The jugal is quite similar in shape to that of Myocastor, but 

 is much narrower ; anteriorly, it ends in a concave suture for the zygomatic 

 process of the maxillary, and does not ascend upon that process. A marked 

 difference from the last-named genus and Capromys is furnished by the 

 lachrymal, which is quite large and forms most of the anterior border of 

 the orbit, while in the two modern genera this bone is reduced to rudi- 

 mentary proportions. 



The frontals are rather short, quite broad, and nearly plane, showing 



FIG. 39. 



Skulls of Octodontidae, top -view. a. Myocastor coypus, x |. b. Capromys fournicri, x \. 



c. Ncorcoinys anstralis, x f . 







no external indications of sinuses ; no well defined temporal ridges are 

 present, but the postorbital processes are quite prominent and in front of 

 each process the projecting supraorbital border is notched. The nasals 

 are of nearly the same relative length as in Capromys, but are less convex 

 transversely ; they are broad, widening somewhat forward ; the anterior 

 end of each nasal has a broad, shallow, lateral notch, much as in Myo- 

 castor, while the hinder ends together form a single convex curve, which 

 fits into a concavity of the frontals. The anterior nares are not unlike 



