NATURAL SCIENCES OF PHILADELPHIA. 331 



lateral stripes whitish yellow. A few of the scales have narrow black spots on 

 their edges, but these are not prominent, and never extend over a scale, ap- 

 pearing as indistinct mottlings of black on the ground color, always on the 

 rows nest the stripes. The head above is light olive ash. The lateral stripe 

 is on the third and fourth rows, and is narrower than in E. p r o x i m a , cov- 

 ering rather less than two half scales. The color below the lateral stripe is a 

 little lighter than that of the back. The exterior dorsal row is much wider 

 than in any of the allied species, each scale being as high as long. The second 

 row is much narrower, though a little wider than the third. The eye is strik- 

 iiigly large, and the superciliaries are raised, rendering the fore part of the 

 crown an inclined plane, yet the muzzle is higher than in E. proxima. 



No. 965, Tucson and St. Magdalena, 160, 86, 21, 24, 6. Major Emory. A. 

 Schott. 



E. mackostemma Kennicott. 



Spec. char. Twenty-one rows of scales. Body rather stout. Head small, 

 narrow posteriorly. Vertical plate much elongated, twice as long as wide. 

 Eight upper labials, sixth largest, seventh sometimes equal. All the dorsal 

 scales broad and short, first row largest, its scales as high as long and slightly 

 carinate ; second smaller, but much broader than the third. Ground color 

 above very dull yellowish brown. Dorsal stripe broad, light brownish, but 

 little lighter than the ground color, and with an indistinct black border. La- 

 teral stripe on the fourth and part of the third row, indistinct, dull yellowish 

 green. Two series of indistinct broken spots along the second and sixth 

 rows. 



Descr. The dorsal stripe is broad and regular, covering nearly three rows, 

 but is dull and indistinct. On each side of it for one and a half scales there 

 is a rather indistinct black border, somewhat as in E. ordinoides. Below 

 this to the fourth row the color is dull greenish brown. On the fifth and sixth 

 rows there is a series of indistinct black spots, each covering three scales, 

 whose keels are of the ground color. This is also the case with the scales in 

 the black border of the dorsal stripe. The lateral spots are one and a half 

 scales wide, and separated by spaces of the same width. The third and fourth 

 rows, particularly the fourth, are lighter, and of a yellowish green or olive 

 color ; the first and second and lower edge of third being a little darker, suffi- 

 ciently define the lateral stripe. On about every other scale of the second 

 row is a series of broken and irregular black spots, formed by the black mar- 

 gin of each side of the scales ; extremely slight as to the contiguous scales. 

 Each abdominal scutum is distinctly edged with black anteriorly, (of course 

 concealed by the incumbent scutum), and some are tipped with black at their 

 extremities, otherwise the abdomen is immaculate. In one specimen it is 

 uniform dark green ; in another, uniform yellowish green. The head is dark 

 brown above, the superior labials but little lighter, and narrowly bordered 

 with black posteriorly. 



One specimen, upon the removal of the epidermis, appears entirely of a 

 pale creamy yellow throughout, but with the black markings, including the 

 border of the dorsal stripe, very distinct. Another specimen is green instead 

 of whitish yellow. 



City of Mexico. Maj. W. Rich. 



This is a very well marked species, and readily distinguished. In color it 

 bears some resemblance to some varieties of E. ordinoides and d o r s a - 

 lis, but it belongs to a different section of the genus, as indicated by the 

 position of the lateral stripe. It is otherwise different from E. ordinoides, 

 in having a very much smaller head and larger vertical phite, the dorsal 

 scales wider, and the stripe more indistinct. From E. Marciana it differs 

 in its very much smaller head and longer vertical plate, in its broader dorsal 

 band, bordered by a stripe instead of a row of spots, and in the absence of 

 the post oral crescentic patch, and broad black borders of upper labials. 



I860.] 



