124 BULLETIN 61^ UNITED STATES NATIONAL MUSEUM. 



be carefully investigated before any delinite conclusion can be 

 reached." 



Elsewhere in its range angustirostris is not known to meet any 

 similar form, but to the northward the known limit of its range 

 approaches that of one which is strikingly like it in many respects. 

 I speak of T. hammondi (Kennicott). The points of similarity be- 

 tween these forms will be discussed Avhen Immmondi is considered 



in detail. 



MELANOGASTER.h 



Deficri/ption. — I have already stated that this species resembles 

 angustirostris so closely as to suggest strongly a near relationship. 

 The head is slender and the eye small. Lateral stripes usually pres- 

 ent, and confined to the second row of scales. The dorsal stripe is 

 iisuall}^ wanting, but may be present on the median row. Dorsal 

 scale formula, 19-17; the labials, 8/10 (very rarely 7/10, 8/9, or 8/11) ; 

 oculars, usually 2-2 or 2-3, occasionally 2-4 or 3-3; ventral plates, 

 139-158; subcaudals, 49-76; proportionate tail length, .19-26. The 

 color above is uniformly very dark brown without distinct spots. 

 Both the dorsal and lateral stripes are indistinct when present. 

 Belly greenish slate or yellowish ash, with a black bar on the base of 

 each ventral, which is prolonged in the middle to form a median 

 ventral band. Throat and supralabials dark yellow. 



Habits and habitat relations. — Like its northern relative, angus- 

 tirostris, melanogaster is apparently quite aquatic in habits. The 

 following account of its habits at the City of Mexico, recorded by 

 Cope, has already been quoted in the discussion of the habits of 

 megalops. 



«Kennicott'8 type of angustirostris (Parras, Coahuila) is not exactly typical of the 

 northern form, as the eye is fairly in contact with two labials; but while it is thus some- 

 what intermediate between the northern and southern forms, it is much closer to the 

 former, as shown by the coloration and the possession of 21-19-17 scale rows, thus 

 making it entirely fair to give this name to the form. 



bThamnopJds angustirostris melanogaster (Peters), Monats. Konig. Preuss. Akad. 

 Wissen. Berlin, 1864 (1865), pp. 389-390. Includes Tropidonotus baronis-mulleri 

 Troschel, Tropidonotus mesomelanus Jan, and Regina mesomelaena Cope. The fact 

 that Peters states that "Diese Art ist bereits von Wiegmann {Preisverzeichniss der 

 Saugethiere, Vogel, Amphibien, Fische, und Krebse, welche von Hrn. Deppe undSchiede in 

 Mexico gesammelt worden, Berlin, 1. Sept., 1550; wieder abgedruckt in Cabanis Journal 

 fur Ornithologie, 1863, p. 54) benannt und unter dem obigen Namen versandt und 

 verkauft worden" has led Cope to credit this name to Wiegmann. Inasmuch, how- 

 ever, as Peters first described the species, he should be held responsible for the name, 

 for Article 21 of tlie International Code distinctly says that " The author of a scientific 

 name is that person who first publishes the name in connection with an indication, 

 a definition, or a description, unless it is clear from the contents of the j^ublication 

 that some other person is responsible for said name and its indication, definition, or 

 description," and Wiegmann, as is well known, gave no description of this species. 



