HERPETOLOGY OF PORTO RICO. 



701 



The question whether Cope's A. rnelanichnus, from Haiti, is iden- 

 tical with the Porto Rican species can not be said to be settled yet. The 

 scale formula seem to be the same but it is not certain that there may 

 not be other distinguishing features. It will be noted that the Alsophis 

 from Mona is referred to the Porto Rican form without hesitation by 

 those having had an opportunity to examine it, but it should be 

 remembered that none of these authors had any Porto Rican speci- 

 mens for comparison and that the identification is based entirely on 

 the seale formula. Under these circumstances the whole question 

 can not be solved until some one is able to compare directly large series 

 from each of these islands. We have such startling- proof of the effect 

 of isolation working with a variable material 

 to produce separate forms of these snakes 

 that it is quite unwarrantable to lump 

 the various names without incontrovertible 

 proof. 



Professor Garman" mentions as a good 

 distinguishing character of the Porto Rican 

 specimens "the narrowness of the lower 

 postorbital." This character is not confined 

 to this form alone, as it is also found in 

 A Isoj > J i As- ant illensis. 



/), scHption.— Adult; U.S.N.M. No.27766; 

 Humacao, Porto Rico; spring 1900; L. 

 M. McCormick, collector. — Rostral much 

 broader than high, barely visible from 

 above; internasal suture shorter than pre- 

 frontal suture; frontal broader than supra- 

 oculars, as long as its distance from the 

 tip of snout, which is shorter than parietal 

 suture; nostril large, between two large 

 nasals; loreal moderate, trapezoid; one 

 preocular, not in contact with frontal; two 



post oculars, the lower one very narrow; temporals 1 + 2; 8 supralabials, 

 third, fourth, and fifth in contact with eye; fifth and following ones 

 suddenly much higher than the others; live lower labials in contact 

 with anterior chin-shield which is shorter than the posterior; 17 rows 

 of smooth scales round the body, with two conspicuous pores near 

 the tip; 173 ventrals; anal divided; 128 pairs of subcaudals. Color 

 (in alcohol) above uniform brownish drab, below whitish; each scale 

 anteriorly tipped with black, posteriorly narrowly margined with 

 black so as to form a regular network; ventrals, except on throat and 

 neck, as well as the subcaudals, narrowly edged with black; a narrow 

 blackish line emphasizes the suture bordering the supralabials above. 



Fig. 170.— Alsophis portoricen- 

 sis. 2 x natural size. No. 27766, 

 U.S.N.M. 



«Proc. Anier. Philos. Soc, XXIV, 1887, p. 283. 



