352 BULLETIN 17 7, UNITED STATES NATIONAL MUSEUM 



left side, nine (the third divided into two) on right side, the fourth 

 and fifth normally entering the eye, the third almost entering; the 

 fifth, sixth, and seventh upper labials highest, with no groove along 

 their upper edges; five lower labials on each side in contact with 

 anterior chin shields, which are shorter than the posterior; 17 rows of 

 smooth scales around the body, with two pores near the tip of each 

 dorsal scale; 189 ventrals; anal divided; 108 pairs of subcaudals. 



Dimensions: Head and body, 830 mm. ; tail, 340 mm. The dimen- 

 sions of the type, M.C.Z. No. 1522, as given by Cope, are: Head and 

 body, 630 mm.; tail, 260 mm. 



Color (in alcohol): Above uniform deep olive-green, not much 

 lighter beneath; a white stripe beginning on the side of the neck, and 

 continuing on the adjoining margins of the fourth and fifth scale 

 rows as far as midbody, where the stripe disappears; a very indistinct 

 black line between the fifth and sixth scale rows, also disappearing at 

 midbody; upper and lower labials suffused with lighter color; some 

 white blotches on the chin ; most of the ventrals and some of the scales 

 on the side of the body posteriorly edged with a narrow light border. 



Remarks. — A direct comparison of this specimen of melanichnus 

 with the examples of Alsophis portoricensis and A. antillensis described 

 by Stejneger in "The Herpetology of Porto Rico" is sufficient to 

 prove that melanichnus is distinct from both, as Dr. Thomas Barbour 

 has indicated. The shapes of the heads are quite different, being 

 elongate to narrow in melanichnus and relatively broad and short in 

 the two Puerto Rican snakes. The elongation of the head is par- 

 ticularly evident between the snout and the eyes in melanichnus; thus 

 the loreal is a little more than twice as long as high and is nearly 

 triangular in shape, while in the other two species the height is about 

 equal to the length. The frontal in melanichnus is longer in propor- 

 tion to the parietals. The real difference lies in the region between 

 the upper labials and the loreal and temporal regions. In portoricensis 

 there is a groove in this region, which is very well developed behind 

 the eye between the upper borders of the fifth, sixth, and seventh upper 

 labials and the temporals, and which deepens to a channel filled with 

 brown pigment and with little pits in the scales. Thus the upper 

 edges of these labials are straightened, and a sharp, straight furrow 

 runs backward from the eye to the beginning of the last labial in 

 portoricensis. The allied antillensis also has this furrow, which is 

 filled with dark pigment and is pitted similarly, although not quite so 

 prominently. In melanichnus, however, there is no indication of such 

 a channel, the posterior labials and temporals being fitted one to 

 another in the customary mosaic style, and the whole region from the 

 lip to the parietal being graduated and smooth, without any furrow 

 or little pits. 



