1102 



REPORT OF NATIONAL MUSEUM, 1898. 



TRIMORPHODON LYROPHANES Cope. 



Tr'imorphodon lyrophanea Cope, Proc. Acad. Nat. Sci. Phila., 1861, p. 297; Proc. 



Amer. Phil. Soc, 1885, p. 286.— Boulenger, Cat. Snakes Brit. Mas., Ill, 1896, 



p. 56. 

 Lycodon lyrophanes Cope, Proc. Acad. Nat. Sci. Phila., 1860, p. 343. 



Scales in twenty-one (in some specimens, for a short distance, in twenty- 

 three) rows rather broad i)osteriorly and upon the middle of the body, 

 not larger upon the vertebral line. The body anteriorly is slender, 

 contracting to a small neck. Tail less than one-sixth of the total length. 

 Head very distinct, the temples much swollen, so that the greatest 

 breadth in life is just posterior to tlie eyes, though the length of head 

 posterior to the angle of the vertical shield is one line greater than that 



Fig. 314. 

 Trimobphodon lyrophanes Cope. 



= 1. 

 Cape St. Lucas, Lower Cahfornia. 



Cat. No. 4fi80, U.S.N. M. 



anterior. Side of the head constricted at the orbits, the muzzle rather 

 narrow and truncate. Rostral plate broader than high, with but four 

 sutural borders, the superior very long; the apex apparent upon the 

 surface of the head. Prefrontals much broader than long; one-third 

 the size of that part of the prefrontals visible from above. Upon a 

 vertical view, the postfrontals ai)pear longer than broad. Occipitals, 

 superciliaries, and vertical developed; the last presenting a right angle 

 posteriorly, and having the lateral borders slightly concave and con- 

 verging; the first not longer, and about as wide as long, in contact with 

 a large scale in their j)osterior, common emargination. Nasal plates 

 distinctly divided, very small, higher than long. Loreal plates two, 

 the anterior higher than long, intercalated superiorly between the pre- 

 frontal and postfrontal, posterior as long as high. Preocculars three, the 

 superior largest, not in contact with the vertical ; the inferior bounded 

 anteriorly by the third upj)er labial. Postoculars three, the inferior a 



