18 PROCEEDINGS OF THE ACADEMY OF [Jan., 



II. OPISTIIOGLYPHA : 



a. — Anterior maxillary teeth elongated; 2 loreals, 



Trimorphodon. 

 b. — Anterior maxillary teeth not elongated: 

 a'. — Loreal present: 



Scale pits present; eye uith vertical pupil, 



SiBON. 



Scale pits absent ; eye with round pupil, 



Erythrolamprus. 

 b\ — Loreal absent, Tantilla. 



III. PEOTEROGLYPHA : 



Scales smooth in 15 rows; red, with black and yellow rings, 



Elaps. 



EUT.a:NIA B. and G. 



I.e., 24 (1853); CMlopoma Cope, Wheeler Surv., 543; Atomarchns 

 Cope, Am. Nat., 1883, 1300 ; Eutcenia Cope, I. c, 645, and Eep. Nat. 

 Mus., 1014; Tropidonotus (part) Boul., L c, I, 192 ; T hamnophis 

 Stej., No. Am. Fauna, 7, 210.' 



Maxillary teeth smooth, gradually increasing behind, last 2-3 

 rather abruptly enlarged; head scales normal; 1 loreal; 2 nasals; 

 2 internasals ; body stout to very slender ; head distinct ; scales 

 keeled, without pits in 17-23 rows; anal entire. 



Hab. — North America and ^lexico. 



The snakes of this genus seem open to every possibility of varia- 

 tion; they exist everywhere in great numbers between the fiftieth 

 and fifteenth degrees of latitude ; many of them are of semi-aquatic 

 habits, and the complexity of their pattern easily runs into irregu- 

 larities, the reckless naming of which has added to the confusion. 

 In The Primary Factors of Organic Evolution, p. G3 (1896), 

 Prof. Cope states that he recognizes forty-nine species and sub- 

 species in this genus. Nevertheless, if the systematist will but 

 remember that heredity does not act with the exact methods of 

 mechanical reproduction, certain fairly definite groups may be 

 made out, to which these anomalies may with some certainty be 

 assigned. 



• In this paper ]Mr. Stejneger endeavors to substitute for the well-estab- 

 lished Eutcenia B. and G. Fiizinger's name Thnmnophu {Si/st. Bept., p. 26, 

 1843), and seeks to remove that author's mideiiued genera from the class of 

 nomina nuda, by the statement that "the simple tact that Fitzinger ex- 

 pressly indicated the type of the genus at once removes them from that cate- 

 gory." It is true that it does so by rule of the American Ornithologists' 

 Union, bat elsewhere, and in my opinion properly, the best usage refuses to 

 sanction these names. 



