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XXI. Observations upon Pelagic Serpents. By Dr. Tuzopore Cantor, Bengal 
Medical Service, C.M.Z.S., M.A.S., &c. 
Communicated July LO, 1838. 
THE Pelagic Serpents have, by several naturalists, been divided into numerous genera, 
all of which are entirely founded upon external characters. In habits and general ap- 
pearance, however, nature has characterized this group so markedly, that it may easily 
be distinguished from all others ; and the arrangement proposed by M. Schlegel’ is such, 
as to make this family, no less than the beautiful sub-family of Mr. Bell’s* Leptophina, 
the two best-defined natural groups of the whole order. 
The reason why their habits, like those of all the Pelagic animals, are but imperfectly 
ascertained, is obvious ; their geographical distribution is entirely limited to the tropical 
seas, and the danger attending the study of these highly-venomous serpents is a con- 
sideration of no small weight. While I discharged the medical duties on the Hon. 
Company’s Marine Survey of the sea-face of the Gangetic Delta, our fishing-nets, kept 
overboard during many months, procured a considerable number of these serpents. 
Although the flood-tide carries them as high up the rivers as the brackish water, yet 
they are purely pelagic, and are no more found in fresh water than on dry ground ; they 
form, par excellence, the natatorial type of the order. 
A comparison with the terrestrial serpents will easily point out how ‘atte has ac- 
complished her end by the most simple and beautiful modification of the general plan 
upon which the order is constructed. 
The skull is very small, and its bones but little developed ; and although the head is 
formed, like that of the other serpents, with venomous fangs and maxillary teeth, it 
presents some slight deviations. The rostrum, instead of being arched, to allow a free 
passage for the tongue, as in the terrestrial serpents, is elongated into a downward-bent, 
pointed shield, which, closing the mouth, prevents the water from entering. The tongue, 
covered by a scabbard opening closely to the chin, is much less developed in these than 
in the terrestrial serpents. As long as the pelagic serpents are below the surface of the 
water, they never make use of this organ; but when out of water, and the animal is 
blinded by the light, it appears of material use as a feeler*. 
1 Essai sur la Physionomie des Serpens, Partie Déscriptive, p. 488. 
2 Bell, Leptophina: Zoological Journal, vol. ii. p. 324. 
3 This is the use generally attributed to the tongue. In a number of Indian terrestrial serpents I have ob- 
served another, perhaps more important function, viz. that of bringing into the mouth various small bodies, such 
as stones, sand, twigs, &c., which they swallow, in order to stimulate digestion. 
