banks that might be considered necessary. I arrived at Colombo in January, 1902, and as soon as a steamer could be obtained proceeded to the pearl banks. In April it was necessary to return to my university duties in Liverpool, but I was fortunate in having taken out with me as my assistant, Mr. James Hornell, who was to remain in Ceylon for at least a year longer, in order to carry out the observations and experiments we had arranged, and complete our work. This program has been carried out, and Mr. Hornell has kept me supplied with weekly reports and with specimens requiring detailed examination.
The steamship Lady Havelock was placed by the Ceylon government at my disposal for the work of examining into the biological conditions surrounding the pearl oyster banks; and this enabled me on two successive cruises of three or four weeks each to examine all the principal banks, and run lines of dredging and trawling and other observations across, around and between them, in order to ascertain the conditions that determine an oyster bed. Towards the end of my stay I took part in the annual inspection of the pearl banks, by means of divers, along with the retiring Inspector, Captain J. Donnan, C.M.G., and his successor. Captain Legge. During that period we lived and worked on the native barque Rangasameeporawee, and had daily opportunity of studying the methods of the native divers and the results they obtained.
It is evident that there are two distinct questions that may be raised—the first as to the abundance of the adult 'oysters,' and the second as to the number of pearls in the oysters, and it was the first of these rather than the frequency of the pearls that seemed to call for investigation, since the complaint has not been as to the number of pearls per adult oyster, but as to the complete disappearance of the shell-fish. I was indebted to Captain Donnan for much kind help during the inspection, when he took pains to let me see as thoroughly and satisfactorily as possible the various banks, the different kinds and ages of oysters, and the conditions under which these and their enemies exist. I wish also to record my entire satisfaction with the work done by Mr. Hornell, both while I was with him and also since. It would have been quite impossible for me to have got through the work I did in the very limited time had it not been for Mr. Hornell 's skilled assistance.
Most of the pearl oyster banks or 'paars' (meaning rock or any form of hard bottom, in distinction to 'Manul,' which indicates loose or soft sand) are in depths of from five to ten fathoms and occupy the wide shallow area of nearly fifty miles in length, and extending opposite Aripu to twenty miles in breadth, which lies to the south of Adam's Bridge. On the western edge of this area there is a steep
