1884.] ■'- ' ^ [Cope. 



cupying five or six rows of scales on the back, narrowing below, where 

 some of them are interrupted. Two of the rings are so wide as to lead to 

 the belief that each of them consists of two rings united, so that the whole 

 number is sixteen. Tail unspotted. The third, fifth, seventh and ninth 

 interspaces from the head have the scales black-tipped, and are wider than 

 the black bands. The skin has an elegant clear blue reflection. 

 From the state of Michoacan, Dr. A. Duges. 



Crotalidce. 



Crotalus polystictus Cope. Proceeds. Acad. Philada., 1865, p. 191. 

 Crotalus triseriatus Wagl. Jan Iconographie des Ophidiens, nee Wag- 

 leri. Crotalus ximenesii Duges, Naturaleza, Mexico, 1877, p. 23, pi. i, 

 figs. 18-20. 



Table land of Mexico. 



I give the comparative characters of this species, and of the allied C. tri- 

 ."imrt^w-sof Wiegmann. I think that Professor Jan has transposed the name 

 of that species to this one. I took a full description of the Crotali in the 

 museum of Munich, from which apparentlj'^ Wagler drew up his descrip- 

 tion (Naturliches Syst. d. Amphibien, 1830, p. 176), and none of them 

 belong to the present species. My notes made in Berlin, which I visited 

 immediately afterwards, state that the specimens labeled C. triseriatus in 

 the museum of the University, where Wiegmann worked, are like those of 

 Munich. 



The G. triseriaius varies more than the C. polystictus. My descriptions 

 are drawn up from five specimens of the latter, and six specimens of the 

 former. 



Two loreal plates, one above the other. Four iuternasals and four pre- 

 frontals, all longer than wide ; three rows of interorbital scuta and scales. 

 Infraorbital scales in two rows of equal size. Four elongate distinct brown 

 spots behind occipital region ; a narrow yellow band across frontal region. 

 A large brown spot below orbit, and one below maxillary fossa. Five 

 rows oHarge dorsal spots. Scales in twenty-seven rows ; labial scuta four- 

 teen ; subcaudal scutella 18 and 19. Generally of larger size. 



One of the five specimens above mentioned has twenty-five rows of 

 scales. < 



The specimens all come either from Guanajuato (Duges), or from the 

 valley of Mexico (Herrera). 



Ckotalus triseriatus. UropsopJius triseriatus Wiegm. Wagler Nat. Syst. 

 Amphib., 1830, p. 176. Crotalus lugubris Jan. Prodrome d'unlconogr. 

 Revue et Mag. de Zoologie, 18o9, p. 81, PI. E. Duges' Naturaleza, 

 ■ Mexico, 1877, p. 25. 



One loreal plate ; two internasals and four prefrontals, wider than long, 

 or the latter, square. Three or four rows of interorbital plates and scales. 

 Two rows of infraorbital sca.les, of which the superior is very small. 

 Colors plainer. Two post- occipital spots ; no frontal band ; no infra- 



