KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 52. N:0O 4. 13 
variation in colour. A closer study of the specimens shows, however, that a certain 
regularity is to be found, and the figures explain in what manner the change of the 
colour appears to be effected. 
Only one of the smallest of the completely developed specimens (8 mm. be- 
tween snout and vent), and possibly some of the somewhat larger ones may be said 
to be uniform black above — the under surfaces and the limbs being already rather 
light. In all the other dark coloured specimens there is at least an indication of the 
colourpattern which is shown in fig. a, and evidently produced in such a way that 
the sides of the back and the upper side of the nose have begin to fade, by which 
a broad dark dorsal band arises, extending from the vent to between the eyes, sepa- 
rated from the still dark coloured sides by a narrower and lighter dorso-lateral stripe. 
In some specimens the light markings are scarcely discernible, while in others it is 
quite distinct, and in some the contrast between the light stripes and the dark bot- 
tom colour is sharply marked. Sometimes the latero-dorsal stripes have a tinge of 
red, and in one specimen from Southern Queensland they were, according to Dr. 
MJÖBERG'S notes, bright salmon-red. 
The next change of colour seems to be that a pair of deep and backwards 
directed notches cut off the anterior part of the dorsal band as a more or less tri- 
angular spot between the eyes (fig. b); we find this spot in most of the specimens, 
and it is also mentioned in the short description of the colour by BoULENGER (Il. c.). 
A process corresponding to this is sometimes to be found on the sacral region as 
well (fig. c). Later on, the remaining part of the dorsal band becomes divided, as 
the figures c and d show, by a light median stripe in two straight parallel narrower 
bands, or it will be cut into by pairs of lateral notches (fig. e), which gradually be- 
come confluent in the middle, thus as a rule, forming two or three curved crossbands 
on the posterior part of the back (fig. f). The foremost of these notches usually 
do not reach each other, thus forming, as is shown in fig. f, a large hourglass-shaped 
spot on the anterior back. Often this spot is mesially divided by a narrow light 
line in two longitudinal, curved markings (fig. g). 
On such a way has arisen the following colour pattern, rather common in large 
specimens: the back light or dark olive brownish grey with a dark triangular spot 
between the eyes, behind this two narrow longitudinal curved spots more or less se- 
parated mesially, and at last on the posterior part of the back two (or three) curved 
erossbands. If a light narrow median line has arisen at the same time as the lateral 
notches, as shown in fig. e, the transverse bands on the posterior part of the back 
are divided into pairs of spots, an indication of which is seen in fig. g. In some 
specimens the dark markings are bordered with white, to some extent marked by 
figs c, e and g. In some at last the dark markings are very indistincet. This can, 
however, only in a slight degree be said about the specimens of this collection on 
which I have chiefly based my description of the colour variations, viz. the collec- 
tion from Perth. Even in these last specimens, however, the bands and spots have a 
tendency to disappear, as is proved by fig. h which shows one of the largest spe- 
cimens (a female) of this collection. The two emarginated dark dorsal bands, rem- 
