128 OPHIDIA. 



are much smaller than the postfrontals, which extend somewhat to 

 the sides of the head. The nasals are large ; the prenasal a little 

 larger than the postnasal ; the nostril excavates equally the inner 

 edge of each of these plates, and is contiguous above to the prefrontal 

 plate. The loral is large and subpentagonal or trapezoid. The upper 

 anteorbital extends to the upper surface of the head, in the shape of 

 a triangle interposed between the postfrontal and the supraoculary. 

 The postorbitals are of equal size. There are six temporal shields, 

 the anterior being the smallest. The upper labials are seven in 

 number, increasing in size from the snout to the angle of the mouth, 

 the seventh being equal to the fifth, and the sixth consequently the 

 largest. The third and fourth are situated beneath the eye, consti- 

 tuting a part of the orbit. There are eight lower labials, the third 

 and fourth being considerably larger than the rest. The posterior 

 pair of mental shields is narrower than the anterior pair and tapering 

 posteriorly. The scales are disposed upon seventeen longitudinal 

 series, increasing in size towards the abdomen ; the external series is 

 considerably larger than the rest. Abdominal scutellae one hundred 

 and sixty-six to one hundred and seventy-two ; subcaudal scutellae 

 seventy-nine to eighty-nine. The preanal scutella is subdivided, and 

 the subcaudal ones disposed upon a double series. Sometimes the last 

 two or three abdominal scutellae exhibit an irregular subdivision. 



Above olive, tinged with brown ; beneath pale-green ; no black dots 

 visible. There appears to be little if any black in the skin be- 

 tween the scales, although the basal edges of the scales themselves 

 are slightly tinged. 



Loc. Specimens of this species were collected about Puget Sound, 

 Washington Territory. 



Plate VIII, fig. 12, represents Bascanion vetustus, size of life. 



Figs. 13 and 14, are profile views of the head; fig. 13 from the 

 left side, and fig. 14 from the right, both of these views being given 

 on account of the labial plates varying in number. 



Fig. 15, represents the head, from above. 



Fig. 16, is the same region, viewed from beneath. 



Fig. 17, represents the outline of the scales ; and 



Fig. 18, the vent, for the chief purpose of showing the preanal 

 scutella. 



Fig. 19, the dorsal scales. 



