RECORD: Günther, A. 1860. On a new snake from the Galapagos Islands [Herpetodryas biserialis]. Proceedings of the Zoological Society of London 1860: 97-98.

REVISION HISTORY: Transcribed (single key) by AEL Data 9.2010. RN1


[page] 97

9. ON A NEW SNAKE FROM THE GALAPAGOS ISLANDS.
BY DR. ALBERT GÜNTHER.

The genus Herpetodryas, being composed of those Dryadidœ, which have the maxillary teeth of equal length and entirely smooth, comprises snakes from America and from Madagascar. The following species comes from the Galapagos Islands, and appears to be the only Snake as yet known to inhabit that group *.

HERPETODRYAS BISERIALIS.
Diagnosis.—Scales in nineteen rows; eight upper labials, three posterior oculars. Light brown, with a dark brown dorsal band, serrated on the anterior portion of the trunk, and formed by a double series of spots on the middle and on the posterior part of the back. A dark brown streak from the eye across the cheek. Belly irregularly dotted with brown.

* The first mention of a Snake on these islands seems to be in Dampier's 'Voy. Round the World.' ed. 7. vol. i. 8vo. Lond. 1729, p. 103:—"There are some Green Snakes on these islands; but no other land-animal that I did ever see."
Darwin says in his Journ. of Research., p. 381, speaking on the Zoology of the Galapagos Islands:—"There is one snake which is numerous; it is identical, as I am informed by M. Bibron, with the Psammophis temminckii from Chile." Although subsequently, in the 'Erpétologie Générale,' nothing is mentioned by Duméril and Bibron about the occurrence of P. temminckii, or of any other snake, in these islands, that determination of Bibron may possibly be correct. If such be the case, there are two species of Snakes in that group of islands.

No. 423.—PROCEEDINGS OF THE ZOOLOGICAL SOCIETY.

[page] 98

Hab. In Charles Island (Galapagos). Typical specimen in the Collection of the British Museum.

Description.—The head is rather depressed, flat, and, like the trunk and tail, somewhat elongate; the eye is of moderate size, with the pupil round. The rostral does not reach to the upper surface of the snout; the anterior frontals are square, the posterior ones about twice the size and subquadrangular; the vertical is rather slender, twice as long as broad; the occipitals triangular and rather pointed posteriorly. The nostril is situated between two shields; the loreal nearly square; the anterior ocular extends to the upper surface of the head, and is in contact with the vertical. There are three posterior oculars, the middle of which is the smallest, the inferior forming a part of the lower portion of the orbit; the temporal shields are scale-like and rather irregularly arranged. There are eight upper labials, the fourth and fifth coming into the orbit. The median lower labial is triangular, and of moderate size; ten lower labials, the first of which is in contact with its fellow, behind the median shield. There are two pairs of elongate skin-shields of equal size. The scales are perfectly smooth, in nineteen rows, rhombic, those of the outer series being rather larger. Ventral plates 209; anal bifid; caudals 108.

The ground colour is a light brownish-grey: a vertebral band, formed by dark brown spots, begins from the occiput, and is gradually lost on the middle of the tail; it is continuous anteriorly, and serrated on both sides, but gradually dissolved into two series of brown spots, the spots of each series being confluent on the end of the trunk; there is a dark brown streak across the temple. The belly is greyish, and finely and irregularly speckled with brown.

inches. lines.
Total length 14 3
Length of the head 0 5
Greatest width of the head 0 3
Length of the trunk 10 0
Length of the tail 3 10

The maxillary teeth are of moderate size, of nearly equal length, in a continuous series, and entirely smooth.

February 14, 1860.

John Gould, Esq., F.R.S., V.P., in the Chair.

Dr. Shortt, F.Z.S., made some remarks on the Civet-cats of India, and the native method of extracting the perfume.

Dr. Crisp exhibited two stuffed specimens of the Cock of the Rock (Rupicola crocea) which had been brought alive to and had died in this country.


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Citation: John van Wyhe, editor. 2002-. The Complete Work of Charles Darwin Online. (http://darwin-online.org.uk/)

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