10. TROPIDONOTUS. 205 
6. Tropidonotus ordinatus. — 
Se oy age knarenngte Me Pen Sone 820 (1837) ; 
idonotus unctatus, Schleg. 8, ii. 
toes § Bibr. Vil p. 582 (1854), . 
—— ordinatus, alge Giinth, Cat. p. 73 (1858). 
ern 8 ig Sa an, Arch. Zool. An, Phys. iii. 1865, p. 210; 
Garm. N. Rept.” p. 24 (1883). 
Eutenia sirtalis, Cope, Wheeler's Rep. U.S. Surv. W. 100th Mer. 
v. p. 546 (1875), maa Proc. U.S, Nat. Mus. xiv. 1892, p. 661. 
Eye moderate or rather large. Rostral broader than deep, 
visible from above ; internasals as long as broad or broader, as long 
as or shorter than the prefrontals ; frontal once and a half to once 
and three fourths as long as broad, as long as its distance from the - 
end of the snout, shorter than the parietals; loreal about as long 
as deep; one pre- and three (rarely four) postoculars ; temporals 
1+2 or 1+3; seven or eight upper labials, two entering the eye; 
five (rarely four) lower labials in contact with the anterior chin- 
shields, which are shorter than the posterior. Scales in 19 or 21 
rows, strongly keeled; the keel on the outer scale, if present, 
weaker than on the others. Ventrals 137-176; anal entire; sub- 
caudals 44-100. Coloration very variable ; a pair of light dots on 
the suture between the parietal shields is nearly constant. 
Total length 950 millim. ; tail 190. 
North and Central America. 
This species may be divided into numerous forms or varieties, of 
which the following are the principal :— 
I. Lateral stripe, if distinct, running along the second and third 
rows of scales. 
_ A. Seales in 19 rows (exceptionally 21). 
1. Seven upper labials, third and fourth entering the eye ; 
scales of outer row keeled. 
MO WORUOUTOR BETIDO. 5... cect co ealce cso A. Forma typica. 
A light vertebral stripe..............0.+0+5 B. sirtalis. 
2. Seven or eight upper labials ; scales of outer row smooth or 
feebly keeled; a light vertebral ee oats one 
and two half scales .........+.+++ C. infernal 
3. Eight (rarely seven) upper labials; vertebral de, if 
present, one scale wide. 
A light vertebral stripe..............s00008 D. eques. 
No vertebral stripe ; rio cross bands ........ E. sumichrasti, 
No stripe, but cross bands ...........s5+- F, phenax. 
B. Scales in 21 rows; eight upper labials, fourth and fifth 
entering the eye; dorsal stripe, if present, narrow. 
A narrow yellow dorsal stripe; belly greyish 
OUWO ME MUNOK .. 0... oc ce se eeeeeeetn sss G. couchit, 
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