434 REPORT OF NATIONAL MUSEUM, 1898. 



superior row consisting" of larger spines and continued beyond the 

 inferior row to above tlie humerus. Tail with a marginal row of spines 

 on the basal half and intermixed larger scales on the superior surface. 

 A second and short row of marginal scales below the longer one, 

 extending posteriorly from the posterior base of the femur. Scales on 

 inferior faces of limbs and tail, except the femur, keeled, the tail most 

 strongly. 



The hind limbs are short, not reaching the axilla. Tail scarcely or 

 less than twice as long as head without the horns. Femoial pores 

 present in males only, 9-12 in each series, which are well separated on 

 the abdomen. 



Jlleasurements (Cat. No. 831()). — Total length, 148 mm.; length to vent, 

 104 mm.; length to gular fold, 24 mm.; length to end of occipital horn, 

 32 mm.; length to base of occipital horn, 21 mm.; width at temporal 

 spines, inclusive, 3G mm.; length of lore leg, 47 mm.; length of fore 

 foot, 17 mm.; length of hind leg, 61 mm.; length of hind foot, 24 mm. 



Color above brown, divided by a narrow paler vertebral strii)e. A 

 dark brown s])ot on each side of the nape, and two rows of three oval 

 or round dark brown spots on each side of the back. Those of the last 

 two pairs are sometimes confluent into two irregular transverse bands. 

 The brown si)ots have sometimes pale borders. Three dark brown 

 cross bands on top of head, and three dark brown bands from the orbit, 

 the anterior two to the infralabials, the last to the extremity of the 

 second temporal horn. Occipital horns reddish brown. Legs and tail 

 with rather smoke brown cross-bands. Inferior surfaces cream color, 

 sometimes with small scattered dusky spots. 



The range of this species exceeds that of any other rhrynosomo. It 

 extends from Dallas, Texas, on the east to Chihualiua, inclusive, on the 

 the west, and from the Gulf of Mexico on the south to southern Kan- 

 sas and Colorado on the north. It does not occur on the Pacific slope. 

 It is very common in Texas and south to Monterey, Mexico, and in 

 New Mexico as far north as Taos. Like other species of the genus, it 

 loves dry places and sunshine. It has a habit of running in roads, 

 where a good many aie killed in ruts, yet a larger number climb out 

 and escape, to the surprise of the traveler, who thinks they are doomed 

 to death. They are favorites as pets, and if they will eat, live a con- 

 siderable time in confinement. They not infrequently, however, starve 

 themselves to death, though their cai)acity to live without Ibod is mar- 

 velous. The horns of this species are more acute than those of any of 

 the others, which makes it more dangerous as an article of diet for 

 snakes. I once found a dead snake with the occipital horns of this 

 species i)rotruding on opposite sides of the vertebral column near the 

 head. 



A specimen with smooth abdominal scales was the basis of the nom 

 iual si)ecies P. plani/rons. 



