Vol. I] VAN DENBURGH— SNAKES OF THE GALAPAGOS ISLANDS 2)27 



with one scale-pit; and Alsophis Fitzinger, 1843, the type of 

 which is a West Indian snake with two scale-pits. The only 

 character which has been held to distinguish these genera is 

 the number of scale-pits. However, since the snakes of the 

 Galapagos Archipelago are certainly congeneric, and since it 

 will be shown that they have scales with two or one or no 

 pits, there seems to be no good reason for recognizing more 

 than one genus for all these snakes— West Indian, Chilian and 

 Galapagos — which agree in every other respect. Any other 

 course would mean the establishment of genera which were 

 in no sense natural groups; for the Hood Island snakes are 

 certainly more closely related to the other Galapagos serpents 

 than they are to the West Indian species which have no scale- 

 pits. It would seem that as differentiation has proceeded, 

 certain of the species in the Galapagos have lost their scale- 

 pits, as others have in the West Indies. 



The Genus Dromicus Bibron 



1842, Dromicus (not Dromica Dejean, 1826) Bibron, in Sagra's Hist 

 Fis. Pol Nat. Cuba, IV, Rept., 1842, p. 133 (type Coluber cursor) ; Bou- 

 LENGER, Cat. Snakes Brit. Mus., II, 1894, p. 118. 



1843, Alsophis, Fitzinger, Syst. Rept., 1843, p. 26 (type Psammophis 

 anhllensis Schlegel) ; Stejneger, Report U. S. Nat. Mus. for 1902 1904 

 p. 699. ' 



1843. Leimadophis, Fitzinger, Syst. Rept., 1843, p. 26 (type Coronella 

 almadensis=D. regmce) ; Stejneger, 'Report U. S. Nat. Mus. for 1902 1904 

 p. 694. ' ' 



. ^^'^^.' Orophis, Fitzinger, Syst. Rept., 1843, p. 26 (type Coronella cha- 

 mtssonis Wiegm.). Carman, Bull. Essex Inst., XXIV, 1892, p. 86. 



1843, Calophis, Fitzinger, Syst. Rept., 1843, p. 26 (type ' Herpetodrvas 

 cursor). 



1854, TcBniophis, Girard, Proc. Acad. Nat. Sci. Phila., 1854, p. 226 (type 

 T. tanhllus=^D. chamissonis) . 



1862, Haliophis Cope, Proc. Acad. Sci. Phila., 1862, p. 77 (emend.). 



1882, Alophis, Stahl, Fauna Puerto-Rico, 1882, p. 70 (err.). 



1884, Ocyophis, Cope, Proc. Amer. Philos. Soc, XXIII, 1884, p 491 (type 

 O. ater). 



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

 Cope, Trans. Am. Philos. Soc, XVIII, 1895, p. 201. 



TT ^.??1' ^«^M'-^ (not of Wagler, 1830), Boulenger, Cat. Snakes Brit. Mus.. 

 II, 1894, p. 126 (part). 



1894, Monobothris, Cope, Amer. Nat., 1894, p. 841 (type Dromicus 

 chamtssoms) ; Cope, Trans. Am. Philos. Soc, XVIII, 1895, p. 201. 



All of the land snakes of the Galapagos Archipelago agree 

 in their dental and hemipenial characters. The maxillary 

 teeth vary from ten to twelve in number, followed, after an 



