700 REPORT OF NATIONAL MUSEUM, 1902. 



1887. Halsophis Cope, Proc. U. S. Nat. Mus., X, 1887, p. 439 (emend.). 

 1894. Dromicus Boulenger, Cat. Sn. Brit. Mus., II, p. 118 (type D. angvlifer), 

 (not of Bibron, 1842). 



The species of this genus resemble those of Leimadophis closely, 

 but may easity be distinguished by the pair of conspicuous pores or 

 pits near the tip of the dorsal scales. 



The type of Bibron's genus Dromicus is plainly stated to be I bfajiber 

 cursor of Lacepede, and D. angvlifer, therefore, can not be so 

 regarded. 



Two species of this West Indian genus occur within our territory, 

 their distribution being exactly parallel to that of the two species 

 of Leimadophis, inasmuch as one inhabits Porto Rico proper (and 

 Mona Island), while the other is confined to the Virgin Islands, Culebra 

 and Vieques. The chief difference in this case is not in the number 

 of the ventrals, which is almost the same in the two species, but in the 

 number of scale rows round the body. 



The} r ma}^ be distinguished as follows: 



a 1 Scale rows, 17; fifth scale row without any distinctive color feature. 



A. portoricensis, p. 700. 

 o 2 Scale rows, 19; every second or third scale of the fifth scale row particolored, 

 the upper half being whitish, the lower half blackish (fig. 174). 



A. antiUensis, p. 704. 



ALSOPHIS PORTORICENSIS" Reinhardt and Luetken. 



1863. Alsophis portoricensis Reinhardt and Luetken, V-id. Meddel. Naturh. 

 Foren. (Copenhagen), 1862, p. 221; authors' separate p. 69 (type 

 locality, Porto Rico). — Peters, Mon. Ber. Berlin Akad. Wiss., 1876, 

 p. 708 (Porto Rico). — Gundlach, Anal. Soe. Espan. Hist. Nat, X, 

 1881, p. 313 (Porto Rico). — Alophis p. Stahl, Fauna Puerto-Rico, 1882, 

 pp. 70, 160. 



1887. Alsophis melanichnus Carman, Proc. Amer. Philos. Soc, XXIV, 1887, p. 

 283 (Bayanion, Porto Rico) (not of Cope?). 



1896. Dromicus sancUc-cmcis var. portoricensis Boulenger, Jahresber. Naturw. 

 Ver. Magdeburg, 1894-1896, p. 113 (Mona).— Meerwarth, Mitth. 

 Naturh. Mus. Hamburg, XVIII, 1901, p. 11 (Mona). 



L896. Dromicus sanctae-crucis Boulenger, Cat. Sn. Brit. Mus., Ill, p. 634 (Mona 

 I.) (not of Guenther). 



From the above synonymy it might be inferred that the present 

 species is most intimately related to Alsophis sancticrucis of Cope, as 

 it has been made a subspecies of the latter by authors who regard 

 A. antiUensis as specifically distinct. Such is not the case, however. 

 This treatment of the three forms is only due to the fact that both A. 

 portoricensis and A. sancticrucis have 17 scale rows while A. antiUen- 

 sis has 19. But apart from the difference in the number of ventrals 

 between the former, a character at least as important as that of the 

 scale rows, the A. portoricencis and A. antiUensis are really more nearly 

 related than either of them is to A. sancticrucis. 



a F r on i P o r to Rico. 



