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P r o c t o t r e t u s n ig r o m a c u l a t u s .
P late IV .— F ig. 2.
Capite brevi, squamis ñeque imbricatis nec carinatis, tecto ; auribus margine anteriore
tridentato; serie unicâ squamarum supralabialium; squamis temporum magnis,
rotundatis, imbricatis; colli {et proecipué plicoe) crassis, elevatis; facie posteriore
femorum omninò granulosâ ; squamis nonnullis ad latera abdominis guloeque emargi-
natis; maculâ transvcì'sè oblonga, nigrâ, supra regionem scapularem.
Tropidurus {Leioloemm) nigromaculatus, Weigm. Act. Ac-id. Coes. Nat. cur. xvii. p. 229.
Proctotretus nigromaculatus, Bibr. i. c. p. 281.
Habitat, Coquimbo, Chile.
D e sc r ip t io n .—H e ad short, th e muzzle ro u n d ed , ra th e r obtuse ; scales o f th e u p p e r p a r t o f th e head
somewhat convex, smooth ; a single lin e o f scales betwe en th e labial an d o rb ita r ; ears ra th e r
large, th e ante rior margin having th re e ra th e r p rom in en t scales, th e middle one b ein g th e
largest. T em p o ral scales somewhat large, smooth, rounded, and imbricated, those towards the
u p p e r p a rt slightly ca rinated ; those o f th e sides o f th e n e c k th ick a n d elevated, those on th e
fold being ra th e r acutely p rom in en t ; scales o f th e back carinated, th e ca rin a te rm in a tin g in an
acu te p o in t ; a few o f th e scales a t th e sides o f th e abdomen an d th ro a t n o tch ed ; th e rema inder
o f th e scales o f th e u n d e r p a rts rhomboidal. T h e scales about th e axilla a n d a ro u n d th e base
o f th e shoulder are g ran u la r an d very smaU, as are those o f th e posterior surface o f th e thighs,
on which p a rt th e re are no imbricated scales as in T r . Fitzingerii. T h e ta il is ro u n d , exc epting
a t th e base whe re it is slightly flattened ; it is moderately lo n g an d slender. T h e an te rio r
ex trem ity plac ed aga inst th e side does n o t re a ch to th e th ig h ; the posterior similarly placed
reaches to th e shoulder. T h e colour o f th is species is yellowish g re y above, with a yellowish
long itu d in a l line on ea ch side th e back, an d two rows o f black spots ea ch m argined with yellow
b eh in d . T h e re is a large an d d istin c t oblong black mark on th e region o f th e scapula, from
which circumstance th e species takes its name. O n th e posterior surface o f th e thighs, towards
th e u p p e r p a rt, are^ th re e or four black dots p lac ed in a line. T h e u n d e r surface is yellowish
white with d a rk g re y dots an d lines u n d e r th e ch in an d throat.
DIMENSIONS.
Inches. Lines.
Length of the head............... 0 5
of the body I 5
of the tail .................................. 2 8
Total length. . . . 4 8
Length of anterior extremity................ 0 8
of posterior extremity ............ 1 2
This species was first described by Weigmann, and subsequently by M.
Bibron, from specimens obtained by Gaudichaud from Coquimbo, at which place
the single specimen brought home by Mr. Darwin was also obtained.