A Monograph of the Sea-Snakes (Hydrophiinee). 
(With four plates). 
By Major F. Watt, I.M.S., C.M.Z.S. 
More than ten years have now elapsed since the publication of Professor 
Boulenger’s colossal work, Catalogue of Snakes in the British Museum, the third and last 
volume of which appearedin 1896. This last volume contains, among other matter, 
a detailed classification and description of the Hydvophiine, which remains the 
standard work on this admittedly difficult subject. 
Within the last few years I have examined all the specimens of this sub-family 
contained in the following institutions: The Royal College of Surgeons, London; 
The Indian Museum, Calcutta; The Natural History Society, Bombay ; The Govern- 
ment Museum, Colombo; The Medical College Museum, Madras; The Bangalore 
Museum; The City Hall Museum, Hongkong ; The Shanghai Museum, and lately the 
entire British Museum collection. In addition I examined in Yokohama a large 
collection made by Mr. A. Owston in the seas about Japan and the Loo Choo Islands, 
a second large collection from the same source, a fine collection made by Mr. 
J. R. Henderson in Madras, and many smaller private collections from various parts 
as well as many specimens obtained by myself on the coasts of India and Burmah. 
I have detailed notes of every specimen examined and propose in the following 
monograph to review this confused subject, which, I venture to think, requires a 
thorough revision ; and this must necessarily entail much allusion to Professor Boulen- 
ger’s work. 
As collections become enriched it almost inevitably follows that with a larger 
series of specimens available, previous views require modification and correction. Itis 
therefore not surprising that my views are in many ways substantially different from 
those held by Professor Boulenger a decade back. Since that authority’s treatment 
of the subject the British Museum collection has acquired, as a matter of course, many 
additions, and the collections in many of the other institutions referred to above have 
grown, in most instances considerably, since any account of their contained material 
has been published. I am very decidedly of opinion that the actual number of species 
is much below that set forth in Professor Boulenger’s work. This authority has 
already in his catalogue, in some instances, united under one heading many forms that 
had been previously considered distinct, and I think the generalisation commenced by 
him should be pushed very much further. 
The conception of aspeciesis of course, to a more or less extent, a matter of personal 
opinion. I shall therefore, in the following remarks, take every pains to set forth in 
detail the reasons in support of my views. But, beyond this, there are discrepancies 
between Mr. Boulenger’s work and mine affecting questions of actual fact ; I refer in 
particular to the supposed presence or absence of grooves in the posterior maxillary 
