VARIATIONS OF GARTER-SNAKES. 159 



nicott and later writers, Tropidonotus collaris of Jan, etc. It is a very 

 distinct form and has seldom been confused with others. In every 

 specimen examined the kteral stripe is on the second and third rows 

 of scales, and the dorsal stripe is, as a rule, confined to the median row 

 for the greater part of the length, although it is usually wider on the 

 nape and occasionally occupies more or less of the adjacent rows on 

 the body. The dorsal scale formula is nearly always 19-17, rarely 

 19-17-15 or 17-19-17. The supralabials are 7 (often), 8 (usually), 9 

 (frequently), or 10 (rarely); the infralabials are usually 10, occa- 

 sionally 11, rarely 8 or 9. The oculars may be 1-2, 1-3, 1-4. Ven- 

 tral scutes 144 (female) to 180 (male). Subcaudals 66 (females) to 

 97 (males). Proportionate tail length .204 (female) to .292 (male). 



The ground color between the stripes is light brown, inclining 

 either to olive or red, and the keels are usually appreciably redder than 

 the rest of the scale. The lateral stripes vary in color from creamy 

 white to light ^^ellow; the dorsal is generally light orange yellow. 



The first row of scales is ordinarily light or dark ash, with occa- 

 sional, paired dark marks at intervals on the upper and lower edges 

 of the scales, the lower mark including the end of the ventrals. In 

 some instances these marks are represented by a single series of 

 spots, each one of which involves the end of a ventral scute and the 

 first and more or less of the second rows of scales, thus encroaching on 

 the lateral stripe and giving it a wavy appearance. There are always 

 two distinct rows of quadrate black spots between the stripes, and 

 these are generally about one and one-half scales wide, and the same 

 distance apart, the interspaces being bluish white. (According to 

 the descriptions of ''dorsalis" and '' ornata^' specimens the interspaces 

 in Texas and New Mexico specimens may be red.) These spots are 

 on the skin, and are usually represented only on the extreme edges of 

 the involved scales, except anteriorly, where they are represented by 

 a pair of large conspicuous nuchal blotches which cover all of the 

 included scales with the frequent exception of the keels, which often 

 retain their reddish color. The edges of the scales in the interspaces 

 are usually white. 



While the arrangement of the spots described above applies to 

 most of the individuals of eques that have been examined, it does not 

 include a number of specimens in which the spots show a decided 

 tendenc}^ to encroach upon the involved scales forming spots similar 

 to those on the skin (ocellata Cope and collaris Jan). In such speci- 

 mens (and these are usually those in which the first row of spots, 

 below the lateral stripe, is better developed) the encroachment of the 

 black pigment upon the scales is generally more pronounced anteriorh". 

 Indeed, it is not uncommon to find individuals with the spots well 

 marked on the scales of the anterior part of the body, but entireh'^ 

 absent posteriorly. Even when distinct on the scales, however, the 



