voi.xnj PROCEEDINGS OP THE NATIONAL MUSEUM. 049 



IMIl. 



The above tuble j;ives but a very general view of the (listnhiitioii 

 of the species, since some of them are restricted to districts ot the re- 

 gions only, whiU' a few si)ecies are known from so few examph's tliat 

 their range is unknown. Of the hitter class are E. hutlerii, E. nitiloris, 

 E. (iHyustirostris, and E. nigrilatus. The E. saehenii is restricted lo 

 Florida, and the IJ. radix to that part ol" the central region that lies 

 east of the Kocky Mountains, entering the eastern region. The widely 

 distributed si)ecies, as E. fiirtali.s and E. ele(jan.s, are represented in 

 special districts by peculiar subspecies, which look very ditferent fiom 

 each other. The E. proxhna has a range which does not coincide with 

 any zoiilogical district, inhabiting eastern ^lexico, Texas, and the Mis- 

 sissippi Valley. 



The following review is preparatory to the comi)lete monograi»ii in- 

 cluded in my Keptilia of North America, which it is expected will Ituin 

 one of the bulletins of the U. S. National Museum. The niaterial (»ii 

 which this is based is mostly contained in that Museum, and I have 

 had access to it through the pernnssion o[ Secretaries llainl and 

 Langley. 



The study of the several liundrcd sjx'cimens of species of this genus 

 which are contained in the National ^Museum and my ])rivate collei'tion 

 shows that in most of the species the number of rows of scales and the 

 nund)er of the labial plates are (luite constant. In only one species, 

 the E. leptocei)hala^ is the number of scale rows varied by the presence 

 or absence of a single row on each side, and in none is the number of 

 hibial i)lates fretiuently variable. The position of the lateral stripe is, 

 as stated by Baird and Girard, very constant. The relative length of 

 the tail is constant within certain limits and in certain species. In 

 some of the species it varies a good deal. The coloration varies within 

 limits iu each species, and often characterizes subspecies with (H)nsid- 

 erable precision, transitional forms in some such cases being rare, and 

 in others more frequent. The species of the Pacific coast present the 

 greatest difliculties to the systemalist. Here the eastern E. sirfalis 

 comes into contact with the western E. elcijans, and some intermediate 

 forms occur. The E. sirtalis parivtalis resemldcs very much the E. 

 el€(/(ins orilinoides, and the E.isirtdli.s sirtali.s resembles a good deal the 

 JE. elegans Uneolata. The E. i)i/ernali.s intervenes between the two. The 

 E. leptocephala appears quite distinct from tlic southernmost coast 

 forms, but it has nielanistic phases which resemble a good deal melan- 

 istic forms of the E. sirtalis; e. g., ?J. s. trilineata and fJ. s. pickerinijii 

 of the northwest coast region of Washington. 



The colors of the young afford some clue to the older of i>robablc ap 

 pearanceof (;olor marks in the adults. As already remarked by 15aird 

 and Clirard, the spots are more distinct in the young than in a<lid!s, 

 both as to isolation from each other and in distinctness of outline and 

 color. When spots disappear and are replaced by a uniform tint, both 

 lighter {E. elegans ragrans), and darker {E. elajans Uneolata and E. 



