G e n u s— L E IO C EPH A LUS . Gray.
L e io c e p h a l u s G r a y i i .
P late X I I I .—F ig . 1.
Cristàdorsalielevatâ; caudâ suh-compi'essâ ; squamis ventralihxis rhomboideis, lævibus;
margine anteriore meatus auditorii quadridentato ; squama occipitali magna.
Habitat, Galapagos Archipelago.
]:)e s c r ip t io n .— H e ad , riew e d from above, forming a n e a rly eq u ilate ral triangle, covered^ with
irre g u la r slightly raised scales. S u p ra-o rb ita l ridge p rom in en t, a n d covered w ith a series o f
e longa ted a n d im b ricate d scales. Oc cipita l p la te large , p en ta g o n a l, n o tc h e d a t its posterior
margin. T h e a n te rio r m arg in o f th e au d ito ry passage is stro n g ly q u ad rid e n ta te , from th e
existence o f four long an d ra th e r narrow scales. Scales o f th e temple obtusely c a rin a ted , n o t
im b ric a te d ; those o f th e hack stro n g ly a n d acutely ca rin a ted a n d disposed m numerous rows,
converging backwards towards th e dorsal crest. V e n tra l scales rhomboidal, n o t ca rin ated .
D o rsa l cre s t elevated, composed o f flat v e rtic a l scales, so closely p lac ed as to co n stitu te an
almost continuous lin e , e x te n d in g from th e n e c k to th e en d o f th e tail. T a il somewhat compressed
a t th e base, becoming n e a rly ro u n d towards th e middle . Scales b en e a th th e fe et and
to es carinated.
CoLOUK.— T h e colour o f th is species is th u s s ta ted in Mr. D a rw in ’s no tes “ U p p e r p a r t clove
b row n, passing in to hlaok brown w ith black spots. Sides slightly tin te d w ith o ran g e ; some o f
th e scales o f th e crest n e a r th e h e a d are wh ite ; belly n e a rly white ; th e whole o f th e th ro a t
before th e fore legs glossy b lack. T h is is th e most common varie ty in th e Archipelago. T h e
black spots are n o t nn&eq u en tly plac ed in waved transve rse bars, an d are sometimes arranged
longitudinally.
DIMENSIONS.
Inches. Lines.
Length of the h e a d 0 9
of the b ody................................... 2 8
of the tail ................................... J _____ 8
Total length 9 5
Of this species, one of the most beautiful in the whole order of Saurians, Mr.
Darwin obtained numerous specimens, one only of which is fully adult. In the
younger individuals the dorsal crest is low and almost inconspicuous. I t differs
very materially from either of the two species previously described, and I have
dedicated it to Mr. Gray, who first distinguished the genus. Mons. Bibron, unaware
th a t Mr. Gray h ad already constituted the genus under the name Leiocepha-
Im, named it Uolotropis. I have, however, retained the former name, as having
the claim of priority.